Rheintocher R1 Missile - Successful Launch Today

[BigMacDaddy]

As you can tell from my threads, today I had a chance to launch a number of rockets I have built over the last few months that have not seen any air time.

The last one that I finally launched was my Rheintocher R1 Missile – well the sustainer portion anyway. People were pretty worried that the canard fins would mess up the CP-CG relationship but it flew really great (it is a wonder what 2 oz in nose will do). I was really nervous to launch this one since I had put so much time into it and I do not have any other BT80 tubes to do another. This is built with 3D printed parts I designed + BT 80 tubes that I got free from Apogee when they shipped me a poster I won in a Facebook drawing. This portion of the model is 57cm and 280 grams (you can get a feeling for scale in the picture w/ my 9yo son holding it). Flew this with a D12-3 today. The full model is around 75-76cm tall (bit over 29") and comes in at around 510 grams with 3 engines loaded if my old posts are correct (you can see the full model in my profile pic).



I also finally ordered some D12-0 engines for the booster (it needs 2x cluster in booster) so hope to launch the full rocket sometime in near future. Was also pleased that my 20-20 rail launcher worked well w/ the 3D printed rail buttons. Some pics from launch pad...



Note: I used paint I had on hand for this (and bought a few different stains but none was spot-on to the prototype). Not ideal that the dark gray is glossy and the light gray is flat (it’s primer). But I usually do not even bother to paint my rockets so baby steps in right direction. Also proved that 2mm basswood will make a really large yet still stable fins (Boeing Bomarc also has some large fins / wings).

 

[BigMacDaddy]

Here is a pic of the full model...

Note: this picture of 3D printed parts is an earlier version when I thought I could get away with a single E-engine in booster. Realized model was too heavy so went up to 2x D engines.

The prototype I saw in VA earlier this summer that inspired me...

 

[Cl(VII)]

AWESOME! Well done.

 

[DigBaddy]

That is really cool! Nice work!

 

[BigMacDaddy]

Now that the sustainer has flown nicely and I have confirmed my 2020 rail based launch setup works decently (along with the 3D printed buttons) - Next I want to launch the full rocket with the booster. Booster will get 2x D12-0 engines. In simulating this I also found an OR error that creates extra non-existent stages in simulations when you have clusters and multiple stages.

Pair of Booster engines need to ignite a D12-3 engine that is several inches away through a BT50 inner tube (w/ a 5 or 6mm vent hole right before the sustainer engine). I am a bit worried about this but have not been able to find various types of fuses or other things people have mentioned I can hang out of sustainer to assure ignition.

The stability with the booster is not as good as for the sustainer alone. However, I also realized in looking at the sustainer that my fin profiles are not totally accurate -- fins are actually more angled towards rear. I will try to correct and recheck stability calculations.

 

[BABAR]

beautiful rocket. I am impressed with stability given those forward canards.

what motor are you simming on the sustainer for the staged flight? if a D12, you may find you can increase your stability margin by dropping to. 24 mm C, or even adapting down to an 18 mm A (I like the 18mm A for sustainers, it has a big nozzle bore which I theeeeenk makes it easier to light when gap staged.)

smaller motor for first flight also has advantage of reducing chance of long walk (or more tragic outcome) if the stack is significantly off vertical at staging. That’s the downside of black powder staging, there are no altitude or tilt lockouts.

since the rocket is already moving at a pretty good clip at staging from the booster (otherwise wouldn’t be stable anyway) it’s hard to put too small a motor in the sustainer for a successful flight, as long as it has enough ejection charge to deploy the laundry.

 

[BigMacDaddy]

beautiful rocket. I am impressed with stability given those forward canards.

what motor are you simming on the sustainer for the staged flight? if a D12, you may find you can increase your stability margin by dropping to. 24 mm C, or even adapting down to an 18 mm A (I like the 18mm A for sustainers, it has a big nozzle bore which I theeeeenk makes it easier to light when gap staged.)

Thanks very much -- those rear fins are really really large so I guess it offsets the forward CP created by the canards...

Smaller sustainer engine is a really interesting idea... I currently was planning 2x D12-0 in booster and 1x D12-3/5 in sustainer. With the 3x D's the stability is calculated at .677 calibers. If I drop the sustainer engine down to an A8 it only goes up to .698 but if I drop to 2x C11 in booster and A8 in sustainer it goes up to .825 calibers. Smaller engine may definitely be a good way to avoid loss of sustainer... Thanks!

 

[BABAR]

Hope it helps.

caveats (aka fecal turbine interaction analysis)

1. What happens if only 1 booster lights? I suspect an unstable flight on one 24mm C, but I also suspect the same with a single D.

2. You have the data, I suspect 2 Cs will be sufficient to get the whole stack up to speed before it leaves the rail. I am more cautious about down impulsing boosters, but I like it if the motor (s) are sufficient

3. I assume both booster motors are ducted to the single sustainer? The good part is it roughly doubles the probability of sustainer ignition (make sure you have adequate vent hole!). The bad is that, if only one sustainer lights, it will probably clear the pad but flop immediately to the ground, THEN it will light the sustainer and you will have a real land shark. Looks like you have a good green grassy field, so fire risk is low .

4. Pack the nose cone and laundry loosely, as the 18mm A will have a less impressive ejection charge than the 24mm C.

Most likely you are going to have a great flight with none of the above concerns realized, but good to be prepared.

wishing you three straight trails and two short walks!

 

[BABAR]

@Angie , don’t know how the black lines appeared in previous post. They were not intentional, indeed I don’t know how to do it even if I wanted to!

 

[Daddyisabar]

Wunderbar!

 

[Tobor]

@Angie , don’t know how the black lines appeared in previous post. They were not intentional, indeed I don’t know how to do it even if I wanted to!

Well I am not Angie, but the unwanted lines are called strikethroughs. To edit text for a strikethrough, first highlight the text to edit (Hold left mouse button and drag) then press Ctrl key and S Key together. To undo a strikethrough, repeat the edit process again.

 

[BABAR]

Well I am not Angie, but the unwanted lines are called strikethroughs. To edit text for a strikethrough, first highlight the text to edit (Hold left mouse button and drag) then press Ctrl key and S Key together. To undo a strikethrough, repeat the edit process again.

Greatly appreciated. I managed to do it with an IPad. I will see what I can do.

Okay, I put “ “ in there for hole(s), used brackets instead of parentheses since I already had the later. Problem fixed.

Except messed up the explanation. If you put an “s” between two brackets it makes a strike through. Better than having your “s” in a crack, I guess!

 

[Bat-mite]

I'll bet that would be the coolest-looking thing on the pads at most launches.

 

[BABAR]

I'll bet that would be the coolest-looking thing on the pads at most launches.

It would be a sad thing if my “s” in a crack was the coolest thing at a launch…….

 

[BigMacDaddy]

I'll bet that would be the coolest-looking thing on the pads at most launches.

Thanks -- that is a huge compliment, I guess I need to go to some club launches!!! I am a bit intimidated.

 

[BigMacDaddy]

Hope it helps.

caveats (aka fecal turbine interaction analysis)

1. What happens if only 1 booster lights? I suspect an unstable flight on one 24mm C, but I also suspect the same with a single D.

2. You have the data, I suspect 2 Cs will be sufficient to get the whole stack up to speed before it leaves the rail. I am more cautious about down impulsing boosters, but I like it if the motor (s) are sufficient

3. I assume both booster motors are ducted to the single sustainer? The good part is it roughly doubles the probability of sustainer ignition (make sure you have adequate vent hole!). The bad is that, if only one sustainer lights, it will probably clear the pad but flop immediately to the ground, THEN it will light the sustainer and you will have a real land shark. Looks like you have a good green grassy field, so fire risk is low .

4. Pack the nose cone and laundry loosely, as the 18mm A will have a less impressive ejection charge than the 24mm C.

Most likely you are going to have a great flight with none of the above concerns realized, but good to be prepared.

wishing you three straight trails and two short walks!

2x C11's seems a bit suspect to me, despite the data (which oddly suggests that model is the fastest off the launch rail).

Yes, both booster engines are ducted via a 'y' to the single sustainer with a vent within less than 10mm of the sustainer engine nozzle. I posted earlier about whether I needed to increase the vent size and consensus said no.

Good advice on ejection charge. Thanks!

 

[teepot]

I wouldn't worry about the gap. Someone on here has gap staged to 51" IIRC.

 

[Ez2cDave]

QUEST Q-JET 24mm D22 Motors . . . Electronic staging.

https://www.questaerospace.com/24mm_White_Lightning_Q-Jets/cat4193206_4883748.aspx

Dave F.

 

[BABAR]

I wouldn't worry about the gap. Someone on here has gap staged to 51" IIRC.

Yup!
working on 72” with black powder F on booster, but haven’t gotten around to the build (although I have the motors and the rail.)

 

[Raptor 2]

Beautiful job on the rocket design and build. Can’t wait for for the full stack launch!

 

[BigMacDaddy]

I finally got back to this rocket and built the booster portion late last night...



I put the final weight and actual CG for sustainer and booster into Open Rocket and I think I need 2oz more of weight in the nose cone for the booster phase to be stable (this is not a very long rocket and it has huge fins on the sustainer + canard fins all the way in the front + cluster of 2x D12-0 engines to lift this heavy rocket). I need to create a compartment + locking mechanism for nose-cone weights so that I do not have to leave these weights in each rocket. The OR sim below is with the additional 2oz and with a 2xD12-0 + C6-3 in sustainer.



It took me a bit of thinking to come up with the twist-lock engine mount / retainer setup for this 2-engine cluster sustainer. It is 3D printed in two-parts (load engine between two parts and lock whole thing into body tube. It has an inner tube that connects into the top valve structure that allows cold gasses to escape but hopefully conveys enough of the burn through to ignite the top engine. I hope this structure prooves strong enough and seems to convey mostly of the force directly through the inner tube to the sustainer.



I am hopeful that my setup will allow the release of a chute for the booster portion. I basically split the transition so that it would hopefully fall away from the rocket as the booster is ejected. Those two parts will be tied to the booster via short kvelar lines and the chute is hidden in there (hope air will catch it and help it fill). Chute is a bit small but hopefully it is enough with those large fins and once booster is unstable (+ lighter once the engines are burnt out). I am a bit worried about the sustainer pealing off before it should and might 3D print a small part to make a slightly stronger connection between booster and sustainer.

 

[Ez2cDave]

I am impressed with stability given those forward canards.

As long as the CG / CP relationship is correct, all should be well. However, I would not fly this rocket in breezy conditions, due to weather-cocking.

TALOS is a good example . . . The 2nd, 3rd, & 4th images are Chris Flanigan's model at NARAM-50 . . . It flew perfectly !

Dave F.

 

[neil_w]

Thanks -- that is a huge compliment, I guess I need to go to some club launches!!! I am a bit intimidated.

Whaaaa?????

No one should ever be intimidated to go to a club launch. You go, fly your rockets, hang out, have fun.

Besides, if anything, it's the other folks who are going to be intimidated, looking at that thing. It's really quite impressive.

 

[Raptor 2]

It’s a real looker! It has a real 1800s look about it.

 

[Scotty Dog]

That is wicked pissah cool.

 

[rharshberger]

Mindsim says that booster is more than likely going to be stable after staging, but I have be very wrong before. Only one way to find out for sure!

 

[Daddyisabar]

Mindsim says that booster is more than likely going to be stable after staging, but I have be very wrong before. Only one way to find out for sure!

Mindsim Rules!

 

[BigMacDaddy]

Mindsim says that booster is more than likely going to be stable after staging, but I have be very wrong before. Only one way to find out for sure!

The CG is pretty far back in the booster because of the two engines (although not totally sure where it will be with 2x spent engines). I like with long rockets how a small parachute will make the whole rocket float down horizontally... Not sure how this will come down with the relatively small parachute, huge fins, decent heft - but I can always glue broken fins...

I do not, however, have anymore BT80 tubes so may need to make buy some if this get trashed.

 

[Pem Tech]

BigMacDaddy I salute you. This has been on my build list for YEARS, but just never had the time. Not only have you created a beautiful scale model but the blasted thing flies!
Bravo!

 

[jqavins]

Here is a pic of the full model...
View attachment 480413

That is one weird looking rocket. In a good way.

what motor are you simming on the sustainer for the staged flight? if a D12, you may find you can increase your stability margin by dropping to. 24 mm C, or even adapting down to an 18 mm A (I like the 18mm A for sustainers, it has a big nozzle bore which I theeeeenk makes it easier to light when gap staged.)

smaller motor for first flight also has advantage of reducing chance of long walk (or more tragic outcome) if the stack is significantly off vertical at staging.

Personally, I would not launch that with less than a C11 in the sustainer. With the final full stack mass, subtracting the difference between the earlier full stack and sustainer only masses, and adding the mass of a spent 18 mm engine, the sustainer mass is now 439 g. The weight is 4.3 N. The drag force at the speed reached at booster burnout is not known (by me) but surely not insignificant.

So, compare, let's say, 4.5 to 6 N to the thrust curves for the A8, B6, and C6 engines. You'll likely be loosing speed even before the sustainer engine burns out.

OK, maybe I've got something wrong, but I really don't think so. Check the sims carefully to be sure it doesn't slow down enough to seriously weather cock while coasting.

Here are the C6 and C11 overlaid. They've got the same total impulse, and the C11 will not have you slowing down during its burn.

Thanks -- that is a huge compliment, I guess I need to go to some club launches!!! I am a bit intimidated.

Whaaaa?????

No one should ever be intimidated to go to a club launch. You go, fly your rockets, hang out, have fun.

Besides, if anything, it's the other folks who are going to be intimidated, looking at that thing. It's really quite impressive.

Yeah, what he said. Add to his list of activities "admire other people's rockets and watch them fly". And since you're profile's listed location is exactly the same as Neil's, you may get to let him prove his own words about intimidation and other people.