Estes - Comanche 3

[Disaster_Guy]

With the smaller size and motor use, this model is easier to keep in the same county that you launch it in.
Happy Friday the 13th.
Mike

But a lot smaller to track and hunt for

 

[Montaro]

...not sure if ya'll knew, but we do have the Mini Comanche 3 coming...PN 2448...should be in house in about 2 weeks. Uses the A10-0 on the bottom and then a various mix of mini engines. With the smaller size and motor use, this model is easier to keep in the same county that you launch it in.
Happy Friday the 13th.
Mike

Damn, now i have to buy it to complete comanche serie

 

[jd2cylman]

Well now. Let's see, I built my second Comanche 3 using all 24mm motors. Maybe the new Mini Comanche 3 needs a 18mm upgrade
Adrian

 

[Fe Dude]

Well now. Let's see, I built my second Comanche 3 using all 24mm motors. Maybe the new Mini Comanche 3 needs a 18mm upgrade
Adrian

D-D-E first flight?

That's a fantastic idea, ima do it.

 

[Rex R]

when they become availible...E12,E12,E12-8 .
rex

 

[UrbanKnight]

...not sure if ya'll knew, but we do have the Mini Comanche 3 coming...PN 2448...should be in house in about 2 weeks. Uses the A10-0 on the bottom and then a various mix of mini engines. With the smaller size and motor use, this model is easier to keep in the same county that you launch it in.
Happy Friday the 13th.
Mike

I did see that and was tempted to try it out, but one thing I noticed (if this helps you in some of your product line decisions) is that local stores (at least around here) don't seem to want to stock things like mini size boosters. Understandable, since they aren't needed often, but the availability of engines plays a role in my decision on which models to build.

 

[JStarStar]

when they become availible...E12,E12,E12-8 .
rex

Are they going to offer an E12-0?

For that combo you'd probably need about an E12-12 for the top stage. :y:

 

[plano-doug]

when they become availible...E12,E12,E12-8 .
rex

Realistically, this thing will be crawling off the rod. By the time the 3rd stage lights, it'll be lucky if it's not already pointing back at the ground. While the forthcoming E12 will no doubt be an improvement over the E9 in terms of lifting ability, it's still not a high-thrust motor (comparatively speaking). Yes, an E12-0 booster will be better than an E9-0 booster. And I will surely buy and fly them. But they're still only moderate thrust motors. Yet they're still quite heavy motors. So the the two upper stage motors will present quite the payload challenge to the 1st stage motor, even in an otherwise very light rocket.

Flyer beware

Doug

.

 

[JStarStar]

Realistically, this thing will be crawling off the rod. By the time the 3rd stage lights, it'll be lucky if it's not already pointing back at the ground. While the forthcoming E12 will no doubt be an improvement over the E9 in terms of lifting ability, it's still not a high-thrust motor (comparatively speaking). Yes, an E12-0 booster will be better than an E9-0 booster. And I will surely buy and fly them. But they're still only moderate thrust motors. Yet they're still quite heavy motors. So the the two upper stage motors will present quite the payload challenge to the 1st stage motor, even in an otherwise very light rocket.

Flyer beware

Doug

Well, the Comanche (or a Comanche-3E variation) is, for the E motors, a minimum diameter 3FNC -- not a huge chunky thing like the Saturn V or the Maxi V-2 (to name a couple rockets which have had E9 launch problems).

https://www.nar.org/SandT/NARenglist.shtml

According to NAR, there will be an E12-0 (as well as a -4, -6, -8)

Also according to the present data, max recommended liftoff weight for the current D12-0 is 13.9 ounces. I would guess the max liftoff weight of the E12 will not be less.

The listed kit weight for the C-3 is 2.1 ounces. (In addition a 'Comanche-3E' would not have the interior motor mounts in Stages 2 and 3 that the 'stock' version does, only thrust rings, so total vehicle weight would be slightly less).

Current E motors weigh about 65 grams (2.3 oz) at ignition so if you went all-up with 3 E motors at 2.3 oz each makes 6.9 oz, add 4 ounces for the rocket (allowing some extra weight for sloppy building), all-up weight should be something around 11 ounces (of course it's also possible some extra nose weight could be needed too since we're sticking heavier motors in the rear end. You'll also have to mess with Stages 1 and 2 to accommodate the longer E motor casings).

We will have to see exactly what the time-thrust curves and total impulse of the E12 turn out to be. My guess is a Comanche-3E would chug somewhat slowly off the pad, but once it starts picking up speed should be fine.

As you note the E12 will not be a "high-thrust" MPR motor (certainly not compared for instance with the AT E30) but it will have a good deal more kick than the current E9. My wild guess is the liftoff characteristics will probably be pretty similar to the current D12 (with a longer burn of course).

Unless you have dramatic problems with rod whip/tip-off my guess is the rest of the flight would be OK. After you drop the first stage your rocket weight is down to about 7.5 oz and lift capacity and airspeed/stability should be no problem any more.

But getting that third stage back could be a problem unless you're launching in the desert. My bet is the odds of SECOND-stage recovery are about 20 percent. That is gonna be a teeny-weeny stage dropping off from way way up. When second-stage burnout occurs the stack will have been under thrust for something like 5 seconds. Not to mention, the second stage in the current Comanche kit is held on by friction-fit tape on the motor -- if you are launching this sucka E12-E12-E12, by the time you get midway in the Stage 2 burn, the drag forces on the fins are going to get pretty stiff and be likely to peel that thing right off of there unless your "friction fit" has the holding power of industrial welding.

Once the actual E12 thrust data is out, somebody will have to RockSim it (I don't have a current version) but I would guess by the time you get to Stage 3 burnout you could be in mach-busting or speed-of-balsa territory. After 7.5-some seconds of thrust that third stage is going to be going like a BOOH.

This would definitely be a roll-the-dice project, probably about $25 of motors going up in a $30 rocket, with a good chance of something going wrong, but it would be fun to watch if somebody can pull it off.


But yeah.... Flyer beware!!

:y: :y:

 

[jd2cylman]

D-D-E first flight?

That's a fantastic idea, ima do it.

Yep, D12-0 to D12-0 to E9-8. First two stages were perfect. 3rd not so much
I can't remember how much nose weight I added. Will have to check later. I think it was 2 or 4oz of clay. Liftoff was perfect. Plenty of upthrust. Way to much down coast when the E9 didn't light :eyepop: crap!
Got another kit. Will give it a go again. I'll get those pesky E9s to light yet :horse:

Adrian

 

[Montaro]

Done and ready to fly !!

I paint based on our university athletic nickname, Tigers University of Nuevo Leon, of course i increass the possibility of lose it

First I applied a blue layer and use a painter's tape to create the tiger print


Then apply several yellow coats


When the paint was dry, remove the painter's tape


Final Finish !


I hope this weekend we can fly it !!

wish me luck !!!

 

[GDJ]

Excellent job!

Honest, this is the first Comanche I've seen that was not painted orange with a silver nosecone.

A refreshing change.

 

[Rex R]

did a quicky sim in OR...1st stage burnout 500', 2nd stage 1500', apogee 4600', topped out at 460mph early in the 3rd stage
rex
edit
E12 data can be found here: https://www.rocketryforum.com/showthread.php?t=28269

 

[Rocketcrab]

...not sure if ya'll knew, but we do have the Mini Comanche 3 coming...PN 2448...should be in house in about 2 weeks. Uses the A10-0 on the bottom and then a various mix of mini engines. With the smaller size and motor use, this model is easier to keep in the same county that you launch it in.
Happy Friday the 13th.
Mike

Nice! [and I'm not a fan of mini-motors] :smile:

 

[chadrog]

Done and ready to fly !!

I paint based on our university athletic nickname, Tigers University of Nuevo Leon, of course i increass the possibility of lose it

First I applied a blue layer and use a painter's tape to create the tiger print
View attachment 68336

Then apply several yellow coats
View attachment 68337

When the paint was dry, remove the painter's tape
View attachment 68338

Final Finish !
View attachment 68339 View attachment 68340

I hope this weekend we can fly it !!

wish me luck !!!

Looks spectacular! If mine looked that nice, I'd be afraid to fly it on anything beyond a C,B,A combo for fear of losing it!

 

[JStarStar]

did a quicky sim in OR...1st stage burnout 500', 2nd stage 1500', apogee 4600', topped out at 460mph early in the 3rd stage
rex
edit
E12 data can be found here: https://www.rocketryforum.com/showthread.php?t=28269

Sounds reasonable -- not quite mach-busting but definitely moving along pretty good (Mach 0.7).

That Stage 2, kicking off into the windstream head over heels at 1500 feet and 300 mph -- i got a sneaking suspicion the usual result of that is gonna be balsa confetti.

:y::y:


What did your sim say about stability and liftoff speed?

The Comanche with its long-skinny 3FNC profile looks offhandedly like stability margin should be OK but putting 3 E motors in the tail end is a lot of weight. Which also applies to Plano-Doug's post about "crawling off the rod."

According to the linked thread the E12 has max recommended liftoff weight of 12 ounces. A "Comanche-3E" would be close, but not over that.

 

[Rex R]

a few notes: 1) I don't know how closely my rocksim file resembles reality. 2) my mods probably need to be adjusted to meet reality 3) properly speaking what I came up with is modified. 4) I had to make the first two stages an inch longer, and stretched the fins to match. 5) the sim used a 48" rod, launch altitude is 900' above sealevel.
with that said, the design report. if you want the ork file please ask.
rex
edit
I added 14 grams to the nose to get the cg where I wanted.

View attachment comanche3e.pdf

 

[JStarStar]

a few notes: 1) I don't know how closely my rocksim file resembles reality. 2) my mods probably need to be adjusted to meet reality 3) properly speaking what I came up with is modified. 4) I had to make the first two stages an inch longer, and stretched the fins to match. 5) the sim used a 48" rod, launch altitude is 900' above sealevel.
with that said, the design report. if you want the ork file please ask.
rex
edit
I added 14 grams to the nose to get the cg where I wanted.

well, just looking at the pdf file it looks pretty close as far as I can see unless I'm forgetting something major from the kit (I don't think so).

Although I think your liftoff weight of 8.57 oz may be a bit optimistic. The motors themselves will be about 6.0 ounces. Estes lists the kit weight 2.1 oz (usually not including paint or glue, plus wadding of course). Probably in the ballpark but my guess is all-up weight will be a bit more.


5.57 caliber stability of course is way more than safely stable, and off-the-rod speed of 62.4 mph should be enough for stable flight, so at least at first glance from the sim it looks like it would fly OK. To me the main question would be when do you reach the "speed of balsa" at 300-400 mph.

:y::y:

(I think I might be inclined on the Stage 3 fins to make the chord a little shorter and the root a little longer -- make the fins stubbier -- to get more fin root surface glued directly to the airframe and a little less fin span sticking out into the slipstream. At 400-some mph those fins are going to be taking a beating.)


Once Estes looses those E12's onto the market I suspect a lot of people will be trying it.

 

[GDJ]

I did a sim on the Comanche by altering the 2nd and 1st stage with larger bodytubing and tabbing all the fins (went to 2mm Birch). With a D12/C11/C6 combination it will do just shy of 2400 feet, 526 km/hr (Mach .43) max speed, Time to apogee is just over 10 seconds.

Stability is 2.61 with all engines installed.

 

[JStarStar]

I did a sim on the Comanche by altering the 2nd and 1st stage with larger bodytubing and tabbing all the fins (went to 2mm Birch). With a D12/C11/C6 combination it will do just shy of 2400 feet, 526 km/hr (Mach .43) max speed, Time to apogee is just over 10 seconds.

Stability is 2.61 with all engines installed.

Not inconsistent with Rex's sim going with E12-E12-E12 -- that is a lot more impulse than D-C-C.

Even considering the Estes E12, like the E9, is really only a "D+" -- 27 n-sec impulse while the classification maximum is 40.

But you're still talking 81 n-sec total impulse, compared to 40 for D+C+C (20-10-10).

Either way that thing is gonna get up and move.

 

[GDJ]

Oh yes. It's a fast one. It's a rocket that needs tabbed Birch fins for reliability.

 

[JStarStar]

Me suspecteth that may be where things go wrong on our hypothetical minimum-diameter "Comanche-3E".

Since TTW fin mounting will not be possible and the fins must be glued/epoxied directly to the tube surface, those fin joints are gonna take a helluva beating when the thing gets going 300-400 mph or more.

:y:

 

[GDJ]

Me suspecteth that may be where things go wrong on our hypothetical minimum-diameter "Comanche-3E".

Since TTW fin mounting will not be possible and the fins must be glued/epoxied directly to the tube surface, those fin joints are gonna take a helluva beating when the thing gets going 300-400 mph or more.

:y:

Is the upper 3rd stage 19mm tubing or the standard 25mm tube with your C-3E? It might be worth tabbing the 3rd stage rocket fins, since velocities are highest for this section.

EDIT: I just viewed the C-3E .pdf file. I see the issues with tabbing the fins. Longer roots on the fins might be in order, with really strong glue / epoxy.

 

[JStarStar]

Is the upper 3rd stage 19mm tubing or the standard 25mm tube with your C-3E? It might be worth tabbing the 3rd stage rocket fins, since velocities are highest for this section.

So far I think it's mainly in the drawing-board/dreamware stage, everybody is just talking about converting the "stock" Comanche-3, which is 3 stages, all 24-mm BT-50.

The stock version uses 24mm D's in the first stage, then 18mm A/B/C's in the second and third.

The idea (I think) is to just take the stock kit and revamp it for the new (shortly to be released) Estes E12's in all three stages.

I suppose a very minor upscale project could be done using BT55 or BT56 tubing, which would allow TTW fin mounting on all three stages, but would also require interior motor mounting which would increase the weight and kind of detract from the "higher-faster-farther" stuff.

Plus then you'd have to rework the whole kit top to bottom rather than just some minor monkeying with the motor mount construction.

 

[GDJ]

Well, here is my interpretation of the Upgraded C-3 rocket:

View attachment Estes %22Comanche - 3 (slight mod)%22.pdf

 

[Rex R]

I was thinking it as a thought experiment . I'm thinking that some folks are thinking a) that one would be able to find it again and b) over estimating the flight loads. tis likely that simply papering the fins would suffice. the bigger problem is the paper tube...though I note that the 'apogee aspire' is touted as being capable of mach busting. I suppose one could use a carbon fibre airframe (performance rocketry cft.95, only $56 usd for a 32" length) .
rex

 

[plano-doug]

With a D12/C11/C6 combination it will do just shy of 2400 feet...

Keep in mind that, while the C11 has more lifting power, its total impulse is about the same as the C6, so the C11 2nd stage motor won't make much difference in the altitude. But having the 24mm 2nd stage mount does leave the door open for a D12-0 there instead (although I'm not advocating that ).

Doug

.

 

[plano-doug]

Also according to the present data, max recommended liftoff weight for the current D12-0 is 13.9 ounces. I would guess the max liftoff weight of the E12 will not be less.

You've done a good analysis here. But keep in mind, the E12, if it has the thrust profile as the D12, will have less net lifting power since it has to lift its own additional weight.

...all-up weight should be something around 11 ounces

11 ounces is about 3 newtons. With an E12 in the first stage, you have only a 4:1 (12/3) thrust/weight ratio, one step down from the 5:1 rule of thumb. While this it still flyable, it's clearly getting into the marginal area.

In my experience, birds that fly under these conditions leave the rod very slowly thus making them much more prone to the effects of any outside influences, be they tip off or wind or rod angle. Bottom line is that this thing can only be flown under ideal conditions - 0 wind, long rod - or things will get real exciting

Doug

.

 

[plano-doug]

I'm thinking that some folks are ... over estimating the flight loads. tis likely that simply papering the fins would suffice.

I agree about over-estimating. But I don't think even papering is needed. Certainly no plywood. All this adds weight in the wrong place, anyway. I'm thinking nearly stock (except for the added tube length for the longer motors) is all that's needed.

A standard balsa fin, attached with with yellow glue and quality craftsmanship, is all that's needed.

BTW, this thread has ventured into the area/topic of over-building. Folks seem anxious to beef this thing up, to prevent bad things from happening, without first establishing that those changes are needed. We should avoid that until it's clear the fins will shred. And quite frankly, the estimated speed 526kph (327mph) should be well within the speed of balsa.

IOW, these fin strengthening enhancements are solutions in search of a problem.

The more likely shred problem will be the chute shredding when it comes out while the rocket's doing 100mph horizontally due to weathercocking. So, if there's some engineering to be done, it's rigging a recovery harness to absorb a high speed deployment.

Doug

.

 

[Rex R]

I found that with a few mods I had a rocket that still looked like a comanche...but simmed out to 4900',480mph. however for that to happen I needed a bonus delay(8.5sec) and a dead calm day. to go higher needs a higher launch site...penrose would do .
rex