Hi this is not a rocket project but a reactor motor project using rocket motors???

Hi I am a well experienced RC modeler mostly doing all sorts of model planes and mostly high speed such as 200mph up to and including pulse jet motors

I now wish to do a rocket motor project attached to a plane just for fun to get super fast speeds sub 300MPH probably 250 MPH for a few seconds similar in concept to
JATO jet assisted take off but better refered to as
JAMS Jet assisted max speed

Already RC model planes are regularly doing 300MPH with turbine pulse jets and DS Dynamic soaring so this project is not out to break any RC model flight speeds records which stand at 420MPH with a turbine jet motor in a dive

So now I am looking for any PRACTICAL solution to liquid fuel reactor(rocket) motors


MAJOR requirements fairly cheap and cheerful even at the risk of much lower power outputs


The project so far

Attach a suitable 4 to 6kg reactor motor to a modified F5D ~1 meter ~(3 foot ) wing span RC model plane for fun to get small very fast runs reaching speeds of 250MPH plus for a few seconds.

Requirements motor run times of some 3 to 5 seconds ideally with ability to PRECISION light up in flight and PRECISION relight several times making say 4 motor runs of 5 seconds each and glide around in between motor burns and electric motor with folding prop or bungee launch take off or both to get to full height to commence first reactor motor runs

The research to date eliminates most off the shelf rocketry solutions for various reasons


The pulse jet solutions is not what I wish to do in this time as the pulse motors are very large for the KG push and cant be easily relight in mid air

Steam reactor power solutions look to be too heavy in this time
but if somebody can prove other wise I am all ears as it looks super cheap
great solution for model cars but too heavy for model planes is my guess

CO2 bottle solutions look to be way too heavy and real low power so not looking practical

Most solid fuels have in-exact firing times eg. non PRECISION and for multi fire ups would require several rocket motors and AP fuel reloadables are crazy money so not practical very difficult to import and a nightmare for all sorts of reasons

Gun powder black powder off the shelf solutions are tiny tiny power like A or B motors and this project is closer to F or G or H or bigger motors and gunpowder large motors dont work as the large grains break up too easy making motor runs fizzle and pop and not work and is mayby to low power

The candy rocket solutions look cheap but again reliable PRECISION light up issues and low power probably make it most likly not a practical solution

Hybrid look to a problem for PRECISION ignition and also they require 9 parts nitric oxide NO2 for one part fuel (epoxy plastic mix ) and nitro oxide NO2 looks to be expensive in Europe difficult to obtain and looks to be fairly heavy and the ready made kits out there are mad money so dosnt look to practical

Liquid solutions preferably would be mono props but those fuels have issues

The best solution Hydrogen peroxide at 98% down to barely usable 80% types are impossible to source in Europe generally and as I live and work all around Europe I prefer to use easy to obtain fuels and hydrogen peroxide H2O2 are extremely caustic (similar to acid affects ) so not practical for cost and protective clothing issues

Nitromethane ( 99% nitromethane 1% methanol standard issue non shock sensitive type )is fairly easy obtainable in larger model plane shops or LHS but sooooooo wicked expensive at often a lot more than ~50 euro ~$80 ~£30 for 5 liters ( ~1.2 usa) gal and each flight of 20 seconds motor run would probably be 1/2 liter 500cc (~ pint) making it ~5 euros ~$7 ~ £3 euro a 20 second fight or ~15 euros ~$20 ~£10 a minute engine run time
As nitro methane fuel is nearly all oxygen and nitrogen molecule it requires 9 times the same fuel as methanol fuel solutions and the worst is its nearly impossible to ignite Nitromethane without extreme pressures and large powerful spark ignition systems and you still really need some outside oxidizer fuel component not much but some approx two parts air to one part fuel or 0.6 parts LOX to one part fuel to get clean burn
Thus probably making reactor motor very complex and most likely not to be a practical solution ???
but is looking to be a very best solution of the bad choices to be made

nitromethane's low oxegen requirements might allow for simpler heavier compressed air solutions

Other fuels like gasoline (petrol)and deseil kerosene all have no oxygen in the fuel and require to carry some form of oxident such as LOX (liquid oxygen) with the complexity and probable high weight issues of LOX but probably not practical as supply of LOX are tricky and looking to be probably very expensive

Other solutions like mix Nitric acid red humorous with kerosene agggghh really not practical

Hydrazine also way to difficult to get and extremely toxic really not practical

Alcohols fuels like ETHANOL METHANOL have some 50% of the molecule as oxygen so thereby needing half the oxygen to supply the fuel(but you need double the fuel compared to petrols fuels) but saving some weight from less LOX but probably not practical as supply of LOX are tricky and probably expensive

The better solutions for me would be to find a simplex way to oxygenate the fuel without LOX if a solution exists

one theory I have is to dissolve KNO3 saltpeter into methanol

salt peter is tricky to get but not impossible

also much more tricky to get is ammonia percaltes but possible if it would work better than saltpeter KNO3

Methanol is easy and fairly cheap at often more than ~15 euro ~$20 ~£10 for 5 liters to get from LHS

I cant find out from research or inquiry"s to umpteen forums will mixing these two components KNO3 saltpeter make the methanol fuel shock sensitive or even explosively unstable imeadiatly or over time span like days whatever

What I do know from research is mixing saltpeter KNO3 to nitro methane will make nitromethane shock sensitive so that is definitly a non starter to use fuel which has any nitromethane added :no:

I am assuming that even if salt peter KNO3 or some such other suitable chemical is mixxed with fuel like methanol there exists the probabilty that there will still be a need for extra oxegen from somewhere else

I was hoping then to use nitro oxide in preference to LOX as it looks cheaper and easier to use than LOX when using small amounts but LOX might be cheaper in large amounts if I am forced to do methanol LOX solutions



Basically once I can solve the fuel oxidation issues i can start to construct a simplex reactor (rocket ) motor to suit the fuel

Mayby somebody who knows the real engineering issues of fuels and motor components might have practical solutions

I shall assume for practical purposes that I can pump the fuel into the motor using simple air pressure from a bike pump into a suitable container such as RC undercarrage air supply tin can or some spring loaded syringe solution whatever but pumping mayby 25cc or one onze a second into reator motor wont be so easy without weighty solutions

I have lots of electric motors brushless lightweight and very powerfull that could be press ganged into driving a fuel pump normaly used in tool boxxes to pump RC methanol model fuels at ~1 onze 25cc per second and lightweight lipo cells that can also drive the motors if nessary but suspect other methods would be lighter

The first trials will be done on RC car on the ground to test the princibles before becoming airborne

Any realy really good ideas shoot but spare me the kerozene turbines and ram jets and pulse jet and expensive AP re-loadables solutions

Also the legal requirements are covered in this is not a rocketry project but a enhaced reactor plane project similar to pulse jet or turbine aircraft and so fits inside the RC plane definitions and would not be restriced by the usual certifation of rocketry where the rocket power is applied to a much smaller craft and the purpose of this reator project s to get low and level flights not vertical flight attributes like rocketry

The rocket motor itself I imangine and hope to keep costs down will probably be some form of model plane exhast pipe mayby tuned pipe or muffler with rear end opened up or suitably modified whatever
becuase of that the metal would probably melt if the engine runs exceeded a few seconds but hopefully would be cheap eneogh and sturdy eneogh for those few seconds followed with a 15 second to 30 second glide around to cool things off and then relight again but I am open to other ideas

I will probably opt to use glow plug with onboard power supply to keep glow lighting driven from one of the RC channels of which my very top-end upmarket RC unit has 12 channels to use

Several thousand replies to date on this issue all strongly THINK that mixxing KNO3 will make methanol explosive but not one once of evidence or imperical facts supplied
so I think that adding to that opinion without facts to back it up is yet another non imperical awnswer
so to save you writing this statement just use the party wave smilys cartoons instead
arty: which is ( party ) and another : ........ : with party in between so you can see it as i cant find a simple explosion smily




JATO

A lot of this is outside the purvey of this forum. Be that as it may, don't think it's possible to do with the criteria you have put forth. The relighting thing is the stopper.

I think your best bet is H2O2, a valve can control the flow and it doesn't need to be relit, the catalyst bed would take care of that problem. The converter from a car would most likely do the job.
NASA uses H2O2 reaction motors to manouver the Space Shuttle so it ought to work for you.

JATO

What you think are the simplest and most promising solutions are the most difficult, complex and expensive. As a professional aerospace researcher with a lot of propulsion background I can state unequivocally that liquid rocket motors of any type are orders of magnitude more complex and expensive than any solid rocket motor, and a multiple ignition motor is a major professional undertaking.

The simplest solution is a solid rocket motor. The ignition issues you fear are nonexistent, and there is at least one B29/X-1 rocket plane RC team in the US. Search the web for the videos.

Another big issue you will face is designing an airplane to take the stresses of high subsonic flight and still fly properly at lower, landing speeds.

Cheers.

Bob Krech
TRF Propulsion and High Power Mioderator

thanks lots of interesting stuff especialy from heada for the etane NO2 solutions

dave carver said:

The relighting thing is the stopper.

Click to expand...

generaly in model planes that is a issue but there exists in flight start up solutions for methanol motors but for cost reasons are not so popular

In a reactor motor without the complexity of moving parts likes pistons etc
I figure its probably not so difficult to get the re-light options and the shut down should be a breeze cut off the fuel supply and if your using fuels like methanol without lots of freezing cold oxidizers like LOX or NO2 where it might require regenetative solutions start up should be posssible if the LOX and NO2 requirements are reduced with other Liquid oxidents

Glow plugs are easy to make hot with a very very single small NiMh cell suppling 4 amps to glow as you only require twenty second glow power and first spray into chamber will have oxegen from the air to ignite the charge and then it would require some oxident to contue the burn

Tricky but possibile I figure

bobkrech said:

The simplest solution is a solid rocket motor. The ignition issues you fear are nonexistent,

Click to expand...

The complexity of flying a plane with the limits of sight for RC control means speeds of 200mph means covering a football feild every second so three seconds burn is three foootball piches in that run
small planes are getting difficult to see at those distances so longer runs are less interesting

A small one second delay starting the fire up sequence will mean cutting short the run to say two seconds or causing other issues and
Also some information on solid fuels is delays of several seconds seem to be the norm from firing the charge to grains igniting and there is another issue coupled of uneven grain burn rates giving impulse of max power for 1.5 seconds and decaying a lot for remaining 1.5 second burn which has other problems

Also a lot of the solid fuels seem to be very heavy for the KG push ratio and mad money per KG compared to other air burning solutions that return the same push

bobkrech said:

and there is at least one B29/X-1 rocket plane RC team in the US. Search the web for the videos.

Click to expand...

yeah i saw the vidio some years back really jaw dropping stuff and this is probably the main reason I wanted to do something simiar but its a one shot flight and that class of AP reloadable looks to be $30 minimum mayby even a lot more for three second burn EEEKKKK

bobkrech said:

Another big issue you will face is designing an airplane to take the stresses of high subsonic flight and still fly properly at lower, landing speeds.

Click to expand...

There exists some issues but model aircraft have been made to carry very heavy loads like ballast for slope soaring in 50MPH winds and heavy early generation battery solutions like NiCads and so solution exist for heavy craft with very high wing loading to do speeds sub 300mph and still land at reasonable speeds like 40MPH

The proposed package reactor solutions would not be intended to exceed 250MPH generaly as it gets to expensive to make model plane solutions that work at speeds exceeding 300MPH so combinations of larger planes smaller motors shorter motor run times etc would be used to keep to speeds of ~250MPH


Being of a model aircraft nature made to do multiple flight with very little maintance the model plane boat and car fraternity has succesfully made complex Pulse jets which consume large amounts of fuel preform very well for 5 minutes and generate easly 4 kgs to 10KGs and sometimes more with many engines running for years and years but the oxegen component comes from the air and therefore means motor is very large

The reactor motor I wish to try out will be hopefully very small say 100 grams with a push ratio of say 40 times making 4kgs of push and fuel tank and oxident of say 700 grams AUW making total 800 grams for power plant would be a lot for F5D plane meant to normaly carry 550 grams of battery and 150 gram electric motor for power in eletric getting speeds of 180mph but suitable wing reinforcements and flaps make it possible to do up to 250MPH and land at speeds sub 40MPH

The princible here will be to copy the best of the Model plane solutions and the best of the rockectry solutions to try to make a simple liquid fueled solution that dont have to e so light like rocketry requires and donst need to be able to resist huge heat as it will do short motor runs and dosnt need to be so effient as rocketry needs to be so as to keep costs down and reduce complexity to the minimum


If the experment was sucessful then larger planes would be needed to go faster than that as 250mPH is maxium for such small planes of these types racing electric craft and probably require some sort of delta shape to benifit from air compression at wing leading edge
but first requirement is to get succesful reusable liquid fueled motor that isnt mad money to make and use like AP solutions


If it works out it might be useful for me and other rocketry guys later on for when I decide to do some rocketry which apeals to my go faster sense of fun

I did talk to one rocketry guy who built a simplex liquid fueled rocket from plans a Canadian type where it used BiProp H2O2 and kerozene and also LOX and kerozene and was amazed at the simplity of the solutions that they used to solve problems but unfortunatly parachutes failures were the death of those rockets after a few flights

JATO

JATO,

What are the insurance issues like in Europe?

Like do you have life insurance? Will you still be covered while you are working with H202, LOX and Kerosene?

What about making your own reusable BP motor. Make a metal case with a welded on nozzle. Put a glow plug at the back of the case and make a hatch in the case which can be opened via a servo. You can have a large bank of BP which then falls into your metal case. The servo could then seal the hatch and the BP could be set off via glowplug. Make this about equal to a D engine - but make a bunch of 'em. Also, you could use a central BP "bank."

I'm just thinking out loud right now - I have no idea if this is feasible.

jderimig said:

What are the insurance issues like in Europe?

Click to expand...

It varies a lot basicaly I avoid doing model aircraft of any sort size in United kingdom or Germany as they are just so heavly regulated
The latin based regions love speed and the regulations are fairly basic stuff not manditory to have insurance but a real good idea to get as it comes cheap with federations like FFAM french modelers assoc.
The real risk is crashes from pulse jet or turbines or electric lipo craft might trigger large forest fires so you have to respect local no fly in certian seasons and locations due to excessive risks from fire
In those cases I assume reactor would be broadly very similar to pulse jet where speeds of 250MPH to 300MPH are the norm or similar to turbines where speeds of 250MPH to ~320 ~350 are the norms so no unusual insurance issues


It would be nearly matamaticaly impossible to get a reator motor of suffient power to drive a plane at speds exceeding 500MPH as the large size of the model planes mean they have enormous drag compared to rocketry and even 250MPH for 15 seconds will be very difficult to achieve

I generaly fly my pulse jet planes in obscure out of the way low poulation sectors as the noise is 150 DB at one mile away so the nearest house will be 20 miles away and the region 10 sgare kilometers around around will contain solo human me or a few pulse jet pilots with me and a few sheep or goats or local aninmalslike rabbits whatever


Needless to say flying will be restricted often to desert locations in middle Spain or wetter regions in north France in May to September due to forest fire risks as is the norm with any flame type modeling like pulse jet or Kerosene turbines but insurance cover would include forest fire damage

Again claims exceeding your cover will go onmto your house policy wjere you have one

Claims exceeding that cuase you hit something expensive like a facory whatever ate the same as any other form of modeling the normal risk

Lucky Europe country side is now vastly depopulated and full of abandoned and empty villages as everybody goes to work in cities or large towns

And if I kill a stray sheep or goat a couple hundred dollars will cover the damage
model plane insurance is generaly good to 1/2 million euros $700,000 in most latin based countries and up to one million in lots of northern countries like Holland and the UK england etc it will be several million euros but all insurance is third party it dont include any models damage to itself or the pilot

I dont have the suffient model aircraft certification to do demonstration model flying at exibitions so I cant fly any models of any sorts at any exibitions where large crowds come to view model planes
I also very much dought inside the next few years i will be upping my certification to do this activity and if I did it would probably not include reactor motor as the turbine jets are already doing at exibitions over 320MPH and they will probably get faster I expect 500MPH from Kero turbines to achieved before 2010 but dont include me in that as it is mega bucks not much change from $10,000 minimum entry stuff

jderimig said:

Like do you have life insurance? Will you still be covered while you are working with H202, LOX and Kerosene?

Click to expand...

I personaly dont have life cover but I used to sell the stuff one time and there should be no extra special hazards doing LOX and Kerosene for life assurance in small amounts
As 98% to 80% H2O2 is impossible to obtain and 60% from hairdressing or food industry is extremly difficult to obtain (60% is 40% water so nearly impossible to use as mono prop and needs to biprop and igniting biprop inside a water shower forget it ) its not an issue

There is lots of info on H2O2 trials and tribulations from early days of armadillo
( armadilloaerospace.com ) and even in the USA he gave up on H2O2 as he could not be garenteed supplies and his budjets were 100 gallon a second engine run so when he with mega bucks cant get what hope has low budget joe soap

Armadillo remains insperation that small liquid fuel motors are possible


LOX is fairly easy to handle and use its boils off very slowly but its main issue is cost in the very small amounts I need ( some 1/4 pint per flight max hopefully less than 100 gramms a flight if other more easy liquid suplimentry oxides solutions exist )

There exists more risk of injury from LOX from cold burns but in the small amount I would require the risks from explosions are neglible and I figure gasoline is far bigger risk than LOX

Kerosene is real safe waxxy stuff hard to ignite and a lot safer than most fuels out there in fact in the olden days I think for medical purposes they used to make patients drink it as it wasnt toxic but i dont intend to drink it and its used every day at model clubs for kerosene turbime aircraft and helicopters

Life assurance risks are low and I should find no extra major problems getting covered but might have issues on the claims as they always promise the sun the moon and stars and then look for every get out clauses even from simple activities like libarain workers who use small step ladders to lift books and then tumble down believe me life assurance companies are real sharks

JATO

ghost said:

What about making your own reusable BP motor

Click to expand...

I iniatly spent a lot of time reasearching using banks of class E estres or similar and realy the problems and costs and complexities of BP( balck powder) and it very very low power yeilds makes it an unlikly solution

however if somebody did prove the feasabilty of it on somehting like model car or boat whatever i could reconsider as making home brew BP isnt too expensive ( lucky I am not UK England based as BP manufactuering is a manditory life sentence for treason complements of GUY FAWKS who used one ton of BP to try to blow up the king of england in 1600 and something )

ghost Like your vidios on heli reactors things

JATO

JATO said:

( lucky I am not UK England based as BP manufactuering is a manditory life sentence for treason complements of GUY FAWKS who used one ton of BP to try to blow up the king of england in 1600 and something )

Click to expand...

Bollocks.

hokkyokusei came across that tit bit on a UK rocketry site explaining why its super cool to import provided you pay the the HAZMAT cost but maufaturing was privilged licence stuff
But as I dont hang out in UK I really dont care less about the UK legal issues as I left the UK last time the day after poll tax came in

another interesting site that i didnt know about obtained from this forum

https://the-rocketman.com/rocketbelt.html


JATO

Why must you do multiple high speed runs in the same flight? Can't you do one, land, reload then take off again? If not then multiple solid motors are probably your best bet. A 3 pack of Aerotech F reloads comes in about 30 euros, so about 10 euros per motor.

What exactly are your cost constraints? I'd be surprised if you could build something cheaper/lighter than solids.

As for the ignition issues, there's plenty of ways of getting your motors to light at the right time.

Again this forums links have thrown up some possible new interesting links

https://www.rocketbelts.americanrocketman.com/steam.html

I may have to revise and revisit steam reactor solutions

The last info was Evil Kenivil rsteam rocket motor bike info site for the grand canyon jump and the weights looked bad from those statistics

statistics on this steam powered reactor motor for full size car from rocket belt site above

Fuel Consumption 23 liters per second
Hp Rating 6250 hp
Thrust 14000N or 3000 lbs
Burn Time 5 seconds
Nozzle throat 66mm diameter
Fuel H2O
Fuel mass 100L

14000n ~1400kg push for 23 litres

scaling down this means one litre can do 60KG of push

100cc or 100grams h20 will do 6kg of push

~80cc 80grams h20 will do 4kg push

80cc*3 = ~250cc `250 grams will do 3second of 4kg push

all not counting steam container and valve and nossle weights

if I could carry three of these units or even two I could live with two burns of 3 seconds if it can be made to be light eneogh and its looks possibly to be super cheap solution

model car guys can easly use this power

or mayby I can carry fuel and heat up each charge of 250cc water in thirty seconds with blast heat but figure four charges of 250 grams is getting very heavy at 1kg for fuel not counting motor container nozzle valve weights

Ikg total for all eguipment motor and fuel is close to probable max but having burnt up 750 grams the landing plane will be fairly light so its not impossible to go to 1.3 KG but its starting to cause serious structural issues if you hit any turbulance you might shred off the wings


One thing for sure even if I dont do a JAMS project i am probably going to do a steam rocket project as they say 30,000 feet is possible and that sounds like a whole lot of fun to do

https://www.rocketbelts.americanrocketman.com/steam/STEAM_ROCKET_1.gif

details in link above

and the stuff should be reusable if the chutes open so keeping cost super low compared to chemical mix rockets

I figure I will launch from beaches and fire out to sea having got proper ATC clearance and borrow my brothers boat to retrive the empty rocket

JATO

JATO said:

hokkyokusei came across that tit bit on a UK rocketry site explaining why its super cool to import provided you pay the the HAZMAT cost but maufaturing was privilged licence stuff

Click to expand...

...and the mandatory life sentences?

JATO said:

But as I dont hang out in UK I really dont care less about the UK legal issues as I left the UK last time the day after poll tax came in

Click to expand...

So why comment on something which you clearly know little about?

init 6 said:

Why must you do multiple high speed runs in the same flight? Can't you do one, land, reload then take off again?

Click to expand...

I could is the simple solution but now we start to enter the clash of the cultures and I dont mean anti anti europe verus anti australia whatever but the comple and total division that exists between two types of modeling culture EG model planes requirements versus model rockets requirements

model planes regularly take off fly and do 300MPH plus and with modern electronics less rarely crash and hundreds of hours use can be obtained from one model and flying times per day can easily be five hours airborne one hour setting up and packing up

model rocketry is often hours setting up then one single ballistic speeds mack one flight or more often with total loss of the rocket and rocket motor system all for a few seconds folowed by several hours packing up and going home

My time contraints obligations to flying model planes means if there is not several runs the landing sequence will interfer too much with the rest of the shedule and I would probably be less interested to continue to do one 3 second burst for every ten minute turn around

Realisticaly this is a gentle entry rocketry project that fits the model plane culture where reusabilty and ultra rapid turn arounds gains highest QUE dos versus disposable culture that dictates the norm in rocketry

So a Scottish model rocketry enthusast will have more in common with a USA model rocketry enthusast than any other form of modeling as they share the same requirements burn lots of $$$ very fast and go very very fast

In time when I get located in a more desolate region compared to the city zone I live in presently I could take on some rocketry culture as real MAX speed probably means real max dollars $$$ but while I am practicing the black art I want to as far as possible retain as much re-usabilty and funcion that model plane cultures and systems can often allow but speeds will be naturaly a whole lot slowwer

init 6 said:

If not then multiple solid motors are probably your best bet. A 3 pack of Aerotech F reloads comes in about 30 euros, so about 10 euros per motor.

Click to expand...

Yep I priced it something like that and that for model plane culture is way way too much money when much cheaper solution exist that perform the same

example the proposed plane will be F5D electric speed flight
normal use they fly at 160mph level for one minute and generates ~1.3BHP power source ~500 gramms NIMH and batteries will last ~20 to ~80 flights so costs ~ $1 mayby $2 per flight
drag from aircraft ~1.5KG @~150MPH

There fore from drag cubic law 300MPH would require to overcome 6KG of drag

so realisticaly 5KG of push will return mayby ~250MPH

the same F motor used in rocket will return probably ~500MPH plus for three seconds but cost roughly $10 per three seconds or $200 per minute EEEEKKKKK:surprised:

200 times more costly

init 6 said:

What exactly are your cost constraints? I'd be surprised if you could build something cheaper/lighter than solids.

Click to expand...

IF you thought some people in model fraternities were tight wads the reality is I spend a lot at the top end of model aircrat in order to gain lots of speed and lots of aircraft modelers fly a lot slower and balk at more $0.10c for a five minute flight so roughly our cost constraints EXPECTATIONS are some 1/100 of what the rocket fraternity would happily part with

Being a bit more pragmatic I can for short periods tolerate standard roketry cost of $10 a three second flight like say twice a year but what to do the other blank periods no way
so plan B is go for finding reusable less fast more pragmatic non rocketry culture solutions while fitting rocketry experments around model planes

For exclusive rocketry uses the solid are cheap especialy the guru like Inverse engineering at www.inverseengineering.com who use cheap and cheerful disposable candy rockets motor solutions with cheap plastic pipes

but for my project even that is too expensive to sustain

I would like to do say mayby three to five flight a day with 12 to 20 second burn per flight and not pay more than $20 for the whole day

Reusable is looking to be the only real option which is a very less done solution for the majority of the model rocketry culture

In fairness when you get into extreme speeds and powers it becomes so very expensive to be reusable that disposable often makes the most sense but this project is not so extreme and therefore makes more sense to check out reusable options

Some of it may be useful in the future for bigger projects but thats unlikely as the the solutions to date look well tried and tested and reusable can get very complicated fast at extreme speeds

init 6 said:

As for the ignition issues, there's plenty of ways of getting your motors to light at the right time.

Click to expand...

In this project the precision start is virtualy manditory

In the ideal senario

the flight will commence with a steep dive having ensured plane is at height from bungee launch of a steep cliff or mountian over a suitable valley or tow plane glider tug whatever

The terminal dive phase involves steep vertical dive and falling from say 500 feet to 100 feet and will mean plane will be at 150MPH as it levels out some two football pitch distance away from RC control unit
The reator motor will light up and run for three seconds accelerating craft to 250MPh where motor will stop and plane will climb under its own momentum to some 1000 feet and proceed to slow down glide around losing height to 500 feet after some 30 seconds and process is repeated

We do this regular with electric drive but the run phase is limited to ~180MPH all cost for plane and motor and airborne gear some $500

To go faster like 200 mph fork out $2000 in electric or gas engine top gear or $1000 in pulse jet and get 250MPH solutions or $6000 plus and get kerosene turbine solutions

When I crash my $500 planes and I have some 5 of them it hurts usualy costs $100 a crash and every 50 flights I crash usaly do high speed passes close to the deck

When i crash my single and only pulse jet at its often a total wipe out crash costs are $1000 euro

If I can get 250MPH on my $500 planes at least crash costs would be halfed so fivty flight one crash is now $10 a flight of say one minute fairly sustainable


if the motor ignition is late by one second the results would be slow run past of 180mph and no better than electric
if the motor starts to soon in the dive the plane will giong to fast for me to pilot out of the dive as I am on the limits already and will cause a expensive crash

Electric motors switch on exactly to request with no delay say less than ~1/2 second are at full tilt so allowing precision control of fast flypasts with very samll planes


Most reasearch suggest solids fuels can vary a lot in ignition start up anywhere from 1 second to several seconds

More precision start ups seem to cost a lot require complex heavy ground gear and still have failure rates of 10% and model planes cant probably carry that type of precision start up stuff at intellegent prices

But as I am not up to speed on all new solutions I will try to remain open to any new concepts or new equipment that might exist that I dont know of

This is the exact opisite of a NASA project where the budget is unlimited this buget contraints my tight wad pocket says if its to expensive I will look to other solutions


anyway often at around this point most rocketry guys brain have gone into a tail spin and they go back to lighting thier fuses wondering why on earth would anybody want to operate to budjet the costs
The fomula is lot of money lots of speed shortened engine run out of sight flight parachute appears after a few minutes salavage a few parts and wait 6 months save up repeat exersize and the others get into a sweat about how come the model plane guys use ^KG with no certification and they need yeaars to reach 6kgs and the difference is simple we do 300mph and rockets do more than 500mph and we strive for reusabilty and rocketry isnt so into it

JATO

A liquid fueled motor will cost more than $10,000 for you to develop, test and finally use. If you make 500 flights with that motor (unlikely as you said you crash an airplane about once every 50 flights) So without using any fuel and assuming you fly the motor for 500 this liquid fueled motor will cost an average of $20 per flight. If we lower the flight count to 100 flights (double your admitted average) the per-flight cost of the liquid motor would be $100. Compare that to an Aerotech G40W solid rocket motor that costs on average $25, has no development costs and is available right now. If the plane were to crash with the motor attached at most the cost would be $25 for that motor. The G40W was picked because it is one of the more expensive single-use solid rocket motors that meets the higher end of your requirements(2.4second burn time producing an average thrust of 40N/s or about 4KG/s). There are cheaper motors available that would drop the cost per flight. The notion of handling such things as LOX or cryogenic fuels is something to very seriously consider. The reason that we model rocketeers do not use liquid fuels is that they are orders of magnitude harder to handle and are not generally safe. A solid rocket motor is very safe to handle, transport and use, more so than most fuels used in model aircraft.

Your concerns about ignition timing may be due to not being as familiar to some of the processes that are used in model rocketry. Model rocket motors go through a certification process that ensures that the motors are manufactured to a certain level of control and thus give repeatable performance. We also have processes that can be used to help ensure that a motor ignites and comes up to pressure in a very short time (less than 1 second) For example, if you were to use an e-match that had been dipped in a good pyrogen that is connected to a circuit that can provide 12V and 2A it should ignite the G40W motor in less than 1 second and more than likely would ignite it in less than 0.5 second. The time it takes to prepare the rocket motor can be measured in multiples of minutes, not hours. A single G40W with an e-match for ignition can be prepared in less than 5 minutes.

Also, the notion that we model rocketeers are not concerned with the re-usability of our rockets is pure fallacy. It is the goal of every person I've talked with and flown with to fly a rocket as many times as possible. There are cases where a rocket will crash, just as there are cases where a model plane will crash. We both strive to keep those cases to an absolute minimum. There have been model rockets that have flown successfully hundreds of times and are still flying today. Some of the motors in our rockets are single use, not the rocket itself.

-Aaron

heada said:

A liquid fueled motor will cost more than $10,000 for you to develop, test and finally use.

Click to expand...

I do hope your projections are wrong

when i see guys like this movie and using simple tin cans with remarkable success my hope is restored its possible to do it more cost effectivly



https://www.youtube.com/watch?v=z4KldD2_lvI&NR=1

heada said:

Aerotech G40W solid rocket motor that costs on average $25,

Click to expand...

EEEEKKKKK
weight is not so bad can carry three of them at some 600 grams not counting reloadable gear holder and ignition material but $25 a pop or say ~8 per second means three in one flight would cost $75 or a flight with three runs and one minute engine run would be $500 per engine run minute AAAAGGGHHHHH



lots of other tecky problems to dwell on and reply to but $25 a pop for a rocket doing 500MPH is probably worth the buzz factor twice a year whatever but for fairly slow 250MPH plane would be way tooooooo much for my tight wad wallet


Will return later when I chew the numbers over

Still looks like nobody knows what happens if you mix KNO3 with methanol or Ethaol or Etane or gasoline or deisel whatever


JATO

JATO said:

when i see guys like this movie and using simple tin cans with remarkable success my hope is restored its possible to do it more cost effectivly

https://www.youtube.com/watch?v=z4KldD2_lvI&NR=1

Click to expand...

Anything you'll come up with similar to that will not be able to lift it's own weight.

You can do similar things (as others have done) for special affects but not as a propulsion device.

Cheapest solution per flight is to go with a short burst, high-power, electric system to augment your sustained power plant for the RC plane.

All of this is way outside the intent of this forum and I'm surprised the topic has lasted this long, in light of other topics that get closed here.

Luck might have it and mayby found the solution

https://www.braeunig.us/space/propel.htm

They say NO2 nitro oxide can be used as mono prop

now all I got to do is figure the catalist and costs etc

Big bottles of nitro loook cheap eneogh and tricky but not impossible to get

will return when I know more

darkhelmet said:

Anything you'll come up with similar to that will not be able to lift it's own weight.

Click to expand...

Low compression tin can is interseting but not so much power but testing and making similar stonger motor trial and error and so forth might work to make a working version

darkhelmet said:

Cheapest solution per flight is to go with a short burst, high-power, electric system to augment your sustained power plant for the RC plane.

Click to expand...

agreed but electric will top out at 230 mayby tops 250 MPH and cost a fortune but will give 4 bursts of 5 seconds on demand but weight of plane landing will be same as take off and most damage is down with heavy planes on landing even into nets

liquid fuels can lose a lot of weight after the run and with big eneogh bungees bricks can be made to take off mayby not fly so good slow but will fly sort of as long as you keep speeds high

And later reactors might allow going faster to 300mph which electric cant do presently but might do in 2009/10 with new solutions

JATO

JATO said:

They say NO2 nitro oxide can be used as mono prop

Click to expand...

NO2 is nitrogen dioxide, a gas you DON'T want to be playing around with.

Nitrous oxide is N2O

Big bottles of nitro loook cheap eneogh and tricky but no impossible to get

Click to expand...

The only nitrous oxide that is "easy" for the average person to get is the stuff used in auto racing, and that is mixed with adulterants like sulfur dioxide which might destroy your catalyst in short order. Fine for a hybrid engine, but may not work well as a monopropellant.

Pure N2O is hard to get (other than small cartridges for whipped cream makers), because it can be used to get high. Unless you have a connection at a research lab or dental office, you will have a hard time getting a tank of pure N2O.

..
EDIT

SCE to AUX said:

The only nitrous oxide that is "easy" for the average person to get is the stuff used in auto racing, and that is mixed with adulterants like sulfur dioxide which might destroy your catalyst in short order. Fine for a hybrid engine, but may not work well as a monopropellant.

Click to expand...

EEEEKKKK didnt spot that before postig below
will have to budjet mayby a new catalist per flight or per few flights
or figure way to clean the gas with filter whatever
I prefer to stick to KISS keep it simple stupid for the first versions
mono prop and no flames makes life so much easier even if there is a lot less power as long as there is eneogh power

SCE to AUX your the man thanks


oh!! NO2 N2O got mixxed up its always N2O and never NO2 so NO2 is a typo
...
Early local cost estimates online from auto car systems are if I spend 600 euro ~$800 or £400 for largest bottle one year rent plus tax plus delivery 37.5KG (~85lbs) of NO2
and each tank for each flight was using 500grams of fuel that would be 75 tanks or 75 flights

I expect costs in USA to be half my costs as Euroland has high tax and costs

and each tank gave SWAG( scientificaly wild assed guess) 12 seconds run and each run was 3 seconds giving SWAG 4kg of push that would be

~8.50 euro ~ £6 or ~$11 per flight and each trhe seconds would be divide those cost by 4 but assuming it not so good and two runs per 500grams double that result still affordable


I havent figured the costs for smaller cyclinders

i havent figured the catalist yet
in fact i will be busy working on this for several weeks to figure out power and then how to do evething

Connectors for example to take NO2 from large cyclinder to smaller ones is ~$100 ~75 euros or ~£50 so its expensive working this stuff

I will have to make a suitable tank for the plane and tha might be heavy metal like say 100 grams to hold 500 grams and then the weight of catalist probably metal might be ~100 grams and than valves and servos

smallest tank I found was 1.5kg for motor cycles

affordable refils from large tank could mean its easier for others who wish to similar make bigger plane say delta type 3kg plane AUW wing probably 50 inch or 1.5 meter and carry 1.5kg tank and fire that off so that might be a 2010 project for me to save up for

That might hit 400 MPH but would cost $2000 plus easy peasy to make a plane strong eneogh to take those powers

All complex stuff as I know nothing about NO2

Future versions when the mono prop is sorted might be able to get secondary ignition to burn the oxegen and some fuel and get more power but thats a long way off

EDIT

https://www.tsinghua.edu.cn/docsn/lxx/mainpage/a/Web/index_files/page0005.htm

and

https://www.wipo.int/pctdb/en/wo.jsp?wo=1994002244

some info on suitable catalyst
very difficult to find info on this subject

Also I want to check out Rebel rockets in Europe to see if I can modify thier Hybrid kits to do the job

I can handle firing up delays of up to two seconds for engine firing provide there is always exactly the same amount of delay time for firing up
probably it is best to assume there will be a predicable delay in heating up catalyst say two seconds and then firing up will be precision 1/2 second later making 2.5 seconds total

Too much devation as in one time 1.5 seconds another time 3.5 seconds could cause this project to terminate with mono prop Nitro Oxide

The main safety issues seem to be don't inhale stuff ,aviod oil grease in contact with gas plumbing etc
Also open valves so as not to cause shock waves and some flamable fumes issue to consider but no big baddies found so far that cant be covered similar to hybrids

JATO

JATO said:

And later reactors might allow going faster to 300mph which electric cant do presently but might do in 2009/10 with new solutions

Click to expand...

Electrics go faster than that right now. In comparing the restartable rocket motor with the added electric propulsion, you are underestimating cost, complexity, and weight. More homework!

JATO said:

I do hope your projections are wrong

when i see guys like this movie and using simple tin cans with remarkable success my hope is restored its possible to do it more cost effectivly

https://www.youtube.com/watch?v=z4KldD2_lvI&NR=1

Click to expand...

That's a tin can with newspaper and gasoline in it, hooked up to an air compressor. How much thrust do you think that's really producing?

Even with a catalyst, N2O isn't going to decompose without high temperatures. What are you planning to use to preheat the catalyst beds, and how does that energy source impact your weight and cost constraints?

this thread made me lol. JATO, you really don't know the first thing about rocketry, and pretending otherwise (like you are) will be hazardous to your health.

BlueNinja said:

That's a tin can with newspaper and gasoline in it, hooked up to an air compressor. How much thrust do you think that's really producing?

Click to expand...

Lol, not much. JATO, these things may seem impressive at first, but they barely produce much thrust. If you look closely, the so called 'jet engine' isn't even secured to the table in any way and it didn't budge once during the firings.

Also, any thrust that it is producing is likely from the compressed air alone - not from the combustion of the fuels. As others have said, solids really are the simplest, cheapest, and easiest solution, and to pretend otherwise would be foolish.

Another note about the video (whicih isn't really the topic of this thread...). To me, it seems like the gas and air are ignited once it exits the engine. That wouldn't really do anything except make a bunch of fire and make the contraption a whole lot more dangerous. Now if it was ignited within the engine, it could actually produce some thrust. Not much, but more than what was being produced originally.

EDIT: Nevermind what I just said. I watched the video again and looked closer and paid more attention. The fuel/air mixture was indeed igniting inside the engine.

jj94 said:

Another note about the video (whicih isn't really the topic of this thread...). To me, it seems like the gas and air are ignited once it exits the engine. That wouldn't really do anything except make a bunch of fire and make the contraption a whole lot more dangerous. Now if it was ignited within the engine, it could actually produce some thrust. Not much, but more than what was being produced originally.

EDIT: Nevermind what I just said. I watched the video again and looked closer and paid more attention. The fuel/air mixture was indeed igniting inside the engine.

Click to expand...

Well, that point right there is the fundamental difference between a flamethrower and a rocket (or jet) - the rocket or jet uses ignition inside the engine to achieve thrust, while the flamethrower uses ignition outside the engine to create flames.

So you want to make a rocket motor that can be restarted at will and costs less than $3 per 'burn'.

You might want to head over to Newton's Third Forum.

There are a lot of seriously techy guys over there who will relish this sort of challenge.