Are we there yet build thread

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

jraice

Well-Known Member
Joined
Jan 27, 2009
Messages
4,166
Reaction score
0
Project are we there yet, was was a earlier thread but seems to have been lost in the cyberspace (I cant even seem to find it with a search) and was dead long before that. It started as a build thread but due to delay in getting the fins ready for assembly it slowed down until there was no interest from you guys, or even me. I now have the fins beveled and their last coat of paint is drying as we speak. The fin tab and section where epoxy fillets will touch have been covered with tape, the fillets will be painted by hand after the rocket is assembled. I plan on having the first flyable design of this rocket ready for a flight in April, and for some K motors in May. The design (see attached rocksim file) is a 2.5" CF airframe with a conical bass wood nose cone, the alt bay/coupler tube is phenolic and will have an internal CF reinforcement... Rocket is dual deploy with drogueless at apogee, and an anchor brand parachute at 500-700'. Fins are hand beveled G10 (1/8") and will be tacked on with CA, and then the fin section will be injected with thin epoxy to secure the fins in place. Motor mount is 54mm, has an aeropack retainer and is secured to the airframe with 3 3/4" long centering rings.

The 3/4" rings were needed because they are so thin, they would be very delicate to handle in the smaller regular sizes, like 3/16" and 1/4" rings. My plan for tonight is to tack the fins in place, and fill the fin area with the thin epoxy (it will have a small amount of milled fiber added to it). Then after several days of curing I will glue the aft CRing into place, and glue th aeropack retaining body into place. I will then make the cosmetic fin fillets and the booster section will be finished. All that remains after that is CFing of the coupler tube and building the alt bay. So far I have the 4 fins cut out and ready to be tacked into place, the upper 2 centering rings are glued on and the motormount/CR assembly is glued in place. The CF tube is also slotted.

First flight will be an I300T, this will prove the design is stable and will make sure the recovery and tracking systems work as planned. If this flight goes A OK a K870R EX wimpy red motor is the plan... at the annual Dairy Aire launch in fresno. It is simulated at mach 1.41 and over 9,000'. Also planned for this rocket is a K1100T and K185W. The K870R is a 5 grain K, and is probably the most impulse this rocket will see... for now. In the near future of May two 38mm strap on boosters will be used to boost the rocket, they will then be released and the standard rocket will go on with an added kick. A K1100T airlit should result in extremely high speeds, but my guess is a K185W will be used for the effect. Two I435's, I300T's or I600R's will be used on the ground, depending on conditions and availability. I am now going to get the fins tacked into place, and take some pictures of the entire rocket to post. Last but not least, the electronics package onboard will be a MAWD for dual deployment and max alt report, and a beeline transmitter.
 
Originally posted by jraice
The K870R is a 5 grain K, and is probably the most impulse this rocket will see...

WHAT!!! No L1400???
 
Need some help, cant get the files small enough to attach them (pictures...)...? The motor mount is 18"s long, and with the limited drogue space I dont think I could fit it... a 6 grain K (K700) would be INCREDIBLY tight fit and probably wouldnt fit. Sorry but no baby L's will be going into it. But with the boosters it has a max impulse of 4400 newtons if I were to put 38/1080 motors in the boosters.
 
Post your tips/help on getting the picture files to fit... I am going to go glue some fins on...
 
If you email them to me at reedgj at gmail.com I can resize them for you.
Reed
 
I simed it on the Loki K250 and it got about 11,5K, That should be an awsome rocket.
 
The AT K250 is far superior ;)
It gets almost 16k on that motor :)
 
Thanks, doing some other work right now, but I will post them soon... RIght now the epoxy in the fin can is curing... How many grains in the loki K250? Right now I have a 4 grain Dr rockets 54/1760 system, so I would like to use that a little... plus they have more propellants at the moment, but I may consider borrowing a loki casing just for that motor. Currently they are not legal in CA yet, though. What is the other smaller Loki K? I know they made the K350 for the L casing... The K250 is a tad bit to big for this rocket. 4 grain is perfect, and 5 grain 54mm motors is the limit. I wish one of the local EXer's had a forumula for an ultra high thrust, or super long burn, 4 or 5 grain motor. Marino is the only person I was able to find, and dont get me wrong, the K870 is one sweet motor! But... I will look into the K250, with what I have heard about loki white that must be one sweet motor! I was actually looking into using a K350 in my freedom won rocket (with airstarts), might have to light all 3 motors on the ground though. Dont know if a K350 can safely lift 35 pounds of rocket.
 
Originally posted by jraice
How many grains in the loki K250?
Can't remember the # of grains, but the case is about 19" long. It fits the 54-2000.

What is the other smaller Loki K?
Loki doesn't make a smaller K casing. The K960 reload also fits the 54-2000.

Dont know if a K350 can safely lift 35 pounds of rocket.
Actually, it would. The Loki K350 has a very high initial thrust of about 250 pounds followed by a steep regressive burn. That's a thrust:weight ratio of 7.14.

I'm thinking of getting the 54-2000 for my MegaBandit. That K250 is very intriguing. Even with a dry weight of 10lbs, the K250, with an initial thrust of about 175lbs, will lift it nicely.

Here's the thrust curves of the recently certified Loki K250, K350, and L930
https://lokiresearch.com/pics/loki_ks.gif
 
Maybe... until they are legit in the sunny state... I will bring my rocket out to XPRS and borrow a casing... and fly the K250 and K960 in this threads rocket... the K350 sounds like the perfect motor for freedom won, but that rocket is to big to do a lot of traveling with, so I will have to wait till loki files CA fire marshel paperwor
 
Here is a dry fit of the entire rocket, minus fin paint and bevels. I took a picture of the entire rocket after painting the fins and beveling them, but it is way to blurry
 
Here is a picture of the beautiful sandman conical (plus a straight section) bass wood nose cone Gordon made for me. Before this picture was taken I soaked (and cured) thin epoxy into the cone for a water proof hard surface. It also gave the cone the darker, and I belive nicer, look.
 
with bevels and purple paint. Didnt paint entire fin to allow space for fillets to hold onto. Fins will be "touched up" and fillets will be painted by hand after the build.
 
Originally posted by jraice
with bevels and purple paint. Didnt paint entire fin to allow space for fillets to hold onto. Fins will be "touched up" and fillets will be painted by hand after the build.

Is this a common technique with larger birds? Isn't easier to get clean results painting at the end?

Geof
 
Originally posted by geof
Is this a common technique with larger birds? Isn't easier to get clean results painting at the end?Geof

No, it's not common. Yes, painting is usually done at the end. But, in this case, I imagine Jordan wants to maintain the natural look of the carbon fiber (it is VERY cool) and just paint the fins & maybe the nose cone, though he may be leaving that natural, too. So, painting after the fins are installed would be a painful masking job and there's the chance paint could still leak through and color the carbon fiber, which you don't want. This way you're guaranteed the carbon fiber retains it's natural appearance. At least this is my reasoning why the fins were painted before installation.

Correct me if I'm wrong, Jordan.
 
Originally posted by cjl
The AT K250 is far superior ;)
It gets almost 16k on that motor :)

Yes, But the AT will not fit that rocket the Loki will, and with thier new K350 that might put a final nail into the future of the K250, esp when the 350 is going to be about $160 vs $250 for the AT plus you can reload the Loki, for the cost of 2 AT's I can buy the case and 2 Loki reloads!
 
That is true. Still, the AT K250 is not replaced (or even close) imo by the Loki K350. The K250 has slightly more impulse, and a significantly longer burn. Both are neat motors though :D
 
Yeah... that is why I did the fins (preserve color of CF and nose cone). I plan on hand painting the fillet and any other area of the fin that I masked off to allow the epoxy to "grip". I will also fix any dings in the paint that can happen during construction. The fin can has been filled with thin epoxy, mixed with a small handful of milled fiber, and the fins feel very secure. The aft CR is also in place. I will be gluing the aeropack, and then making the external fin fillets this weekend. I plan on bringing the fin section to show to some experienced mach breakers to see what they think. Then I will finish up the alt bay work and fly this sucker on a test flight with my first I300T. I cant wait to add some strap on boosters and get a max thrust in the mid L range. Two J570's, maybe even two J825's (same casing, 38/1080) redline motors if they come out in time, and then airstart a K185W! That would be a pretty nice flight. I might hold off on the boosters for a while though, I want to get some more flights in with just K motors, and maybe even a LOKI K250 or K960 flight... I want to hold off on the pricey flights for this rocket later this year so I can afford a freedom won launch. I want to do a loki K350, then airstart two J400 smokey sam motors. Another possiblity is a K350, and two I110's, all lit on the ground!
 
Here is a picture of the aft of the rocket with the fins and aeropack retainer friction fit. Fins have yet to be beveled
 
Here is the entire rocket dry fit, I have a picture with some paint on the fins and with the fins beveled, that I will also post... But this one turned out a little better.
 
Here is the amazing custom nose cone made by sandman... it was soaked with thin epoxy and it much tougher and smoother. I did it mostly for waterproofing the cone.
 
one of the four beveled and painted G10 fins. Notice the small holes randomly drilled in the tab, those allow the thin epoxy injected into the fin can to bite on the fin better, and some were place where the external fillets will go.
 
Here is the rocket friction fit with painted fins. I have decided to hold off on a second freedom won launch until next October and go for it with this rocket, and use the strap on boosters. Ray say's they will be coming soon, and I am ordering the tubing for them tonight. One question, is a recovery system required for a strap on booster, if I can prove it is unstable and will fall in a controlled manner? It would make it a lot easier if a recovery system was not needed. One of the biggest reasons would be that it would allow EX motors (no built in ejection systems) to be used. There was some confusion on my part, and the EX motor being made for this rocket is a K870WR. If I didnt need a recovery system for the boosters I would be able to fly that motor, and two 38mm WR motors. This would be a much cheaper flight comared to a commercial 5 grain 54mm motor and two 38mm 6 grain motors. I have decided to make the booster long enough to hold 6 grain 38mm motors. I dont think I will ever use two J570's, because of problems when they are used in high speed flights, and because the casings would be harder to find (I am borrowing AT casings for the commercial booster flight). So I am planning on flying it on a pair of I284W's or J350W's, and a central K185W. The booster will be deployed a tad bit before true burnout (as the thrust becomes irrelevant) and the main rocket will continue up.

I will post pictures of the booster hardware when it arrives. It is a pryo release system. The back of the boosters and main body will have a "pivot" (allows it to fall off the rocket in an orderly manner by pivoting at the aft of the main rocket). The top uses some sort of pin to release the booster and main rocket, then the pivot allows the booster to fall away from the main rocket. At this point the boosters will either tumble back, or the main motors ejection charge will eject a long harness so they flat spin down to the ground. I will post the booster rocksim file later tonight, after I do the final work on it.
 
Back
Top