RC Bomarc rocket glider

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burkefj

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I have an attachment to Bomarc's since my fathers first assignment at Boeing around 1958-59 was on this program. I've been trying to see if I could design a tube based RC rocket glider of a bomarc that was light enough to glide reasonably well but not have to eject anything or move balast. This is based on .021 thickness 2.6" bt-80 tubing, wing loading is 12 oz/sq foot.

This model is nearly identical in size to the madcow version, 2.6" diameter, 45" long, with a slightly upsized 21" wingspan., but weighs about 1/3 of the rtf madcow version.

The the coupler and forward tube are removable in case I need to get at the ramjet mounts or wiring. The rear of the coupler is held in place by two screws and the rail button flange nut. The forward tube is held in place with plastic push/pins from madcow. The ramjets are bt-60 tubing and have a thin ply facing plate with a hardwood spike and the shoulder is stacked depron foam.

The ramjets have carbon fiber rods through the tubes and the pylons and will hopefully hold up to landings. Only 3/4 ounce of nose weight was needed.

The nose cone is friction fit with tape and the reciver and battery go at the front of the body tube held in with velcro, I remove the nose cone to plug in the battery, simple.


WP_20160103_12_15_51_Pro.jpgWP_20160103_12_16_01_Pro.jpg
Frank
 

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tab28682

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On the subject of slightly more weight added in support of a full body shape, I think that is not a bad trade off to make.

The wing loading goes up slightly and you do lose a bit of the fuse planform area that supplies some of the lift, but you still get a bit of lift from the round fuse and you get rid of a good bit of intersection drag on the fuse.
 

burkefj

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Yes I am, I'm glad this year I was able to try and finish some things I've been thinking about for a long time, mostly with success....

Frank


Looks like you are having way to much fun with these foamies Frank :)
 

burkefj

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What would you like to see in more detail? I can take more pictures of any area. I haven't finished it because I want to test fly it first and confirm thrust line/glide trim etc before I invest more time.

Wowzers....
More pics please.
 

burkefj

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Got out inbetween freezing rain showers to get in a maiden. I was worried about strength of the ramjets on landing in grass, but no issues. I was able to grease the second landing on the runway matting, again no problems.

I chose a thrust line just below the wing against the inside top of the body tube. It was a swag based on my profile thrustline being right on the wing centerline, and this model slightly below which would provide some pitch up, countered by a bit more draggy ramjets on this model. Turned out to be spot on.


Frank
 
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aerostadt

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I am surprised that the front blockage on the simulated ramjets doesn't create a lot of unnecessary drag or they just there for static display.
 

burkefj

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No, they are there for flight as well, doesn't seem to be much of a problem. I wanted to do a more tapered ramjet input, but weight here is critical and they have to take the brunt of the landing, so I went with what I did. The frontal area on the ramjets isn't much worse than the madcow kit and they are much ligher than solid balsa at that size.

I am surprised that the front blockage on the simulated ramjets doesn't create a lot of unnecessary drag or they just there for static display.
 
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burkefj

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Has flown now on Estes E-12-0 plugged with epoxy at the front so they don't eject, or aerotech E-12 RC motors.
 
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burkefj

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After several flights, good news is landing on the nacelles hasn't been an issue so far.

Frank
 
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burkefj

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Got a few more flights in today.
 
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burkefj

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Ok, got 7 more flights on E-12's today .It won't set any glide records but it was a good challenge trying to get a full tube based bomarc to fly RC and now with 17 flights on it in 3 days and no damage....I feel that's worth something....now I'm out of E-12 motors... 16.7 oz rtf now . I was relying on some tape on the front/bottom of the nacelles for landing protection but it was rubbing off, so put some nylon wing guards on the bottom, ground down so that they are just stubs and that did the trick and I don't need to re-tape them after flight now.
 
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TheTellurian

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ROFL :roll:

That was great!


Richard :) :)
 
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tab28682

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Looking good, Frank.

Time to roll a Depron tube for a 3"-4" diameter version of a Bomarc for a G25.....;)

Speaking of Depron...years back I was involved with FanTastic Models, who became, for a while, the leading US cottage industry producer of small molded Depron electric RC models circa 2001-2007. Also learned a few things when doing the SR-71 for HobbyLab.We figured out all the tricks to molding Depron repeatably. Not impossible for a hobbyist to do in a garage with the right vac forming machine.
 
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burkefj

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Curious to try it on the older e-15 motors for the hobbylab SR-71 if I ever find any.

Frank
 
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Sooner Boomer

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Sweet rocket! I really liked flying the Estes one I had (no RC of course...).
 

georgegassaway

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Frank,

Another really nice project!

Some comments / ideas.

I notice at the end of some of the burns, sounded like there is thrust spike, with extra smoke too. If you are not already doing so, you could smear the front end of the grain with petroleum jelly to inhibit the burn along the front face of the grain as it nears burnout.

For other fliers who are new to using endburning reloads, if you do not inhibit the front end of the grain with petroleum jelly or similar, as the concave-curved flame front nears the front end it will first burn thru the center of the front of the grain, then instantly the flame will spread across the entire front end of what is left of the grain, causing a spike in thrust. So the petroleum jelly prevents that from happening.

The ramjet pods are holding up well with your protective methods, so maybe this idea is not worth doing. Rig up a sort of reverse pop-pod mount on each ramjet pod pylon, where the friction is tight enough not to slide off on boost, but can slide off backwards on landing. But that would add some weight so unless you start to get damage and need a fix perhaps not worth it.

You are more bold for first trim flights than I am! For E6 models, I do first flights on a D7, or for G12 models, first flights on an F13. So if things get bad, I don't have another 4-5 seconds of boost to try to hang onto. Well, same deal for pretty much any R/C RBG I fly, making lower power boost trim flights first.

BTW - a generic tip for anyone who does reloads,my favorite container for petroleum jelly is to use the little squeeze tubes of Vaseline lip therapy as seen below. Not as cheap per ounce as a jar, but VERY convenient to use and much easier to put into a range box.

- George Gassaway

 
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rharshberger

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Frank,

Another really nice project!

Some comments / ideas.

I notice at the end of some of the burns, sounded like there is thrust spike, with extra smoke too. If you are not already doing so, you could smear the front end of the grain with petroleum jelly to inhibit the burn along the front face of the grain as it nears burnout.

For other fliers who are new to using endburning reloads, if you do not inhibit the front end of the grain with petroleum jelly or similar, as the concave-curved flame front nears the front end it will first burn thru the center of the front of the grain, then instantly the flame will spread across the entire front end of what is left of the grain, causing a spike in thrust. So the petroleum jelly prevents that from happening.

The ramjet pods are holding up well with your protective methods, so maybe this idea is not worth doing. Rig up a sort of reverse pop-pod mount on each ramjet pod pylon, where the friction is tight enough not to slide off on boost, but can slide off backwards on landing. But that would add some weight so unless you start to get damage and need a fix perhaps not worth it.

You are more bold for first trim flights than I am! For E6 models, I do first flights on a D7, or for G12 models, first flights on an F13. So if things get bad, I don't have another 4-5 seconds of boost to try to hang onto. Well, same deal for pretty much any R/C RBG I fly, making lower power boost trim flights first.

BTW - a generic tip for anyone who does reloads,my favorite container for petroleum jelly is to use the little squeeze tubes of Vaseline lip therapy as seen below. Not as cheap per ounce as a jar, but VERY convenient to use and much easier to put into a range box.

- George Gassaway

Thanks for the reminder George about inhibiting the face of endburners, I plan on flying some of AT RMS ones pretty soon.
 

burkefj

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Hi George, thanks for the comments.

For the pods, there is no issue currently, they seem plenty strong enough, and the carbon rods go through into a coupler so it is even stronger.


Story on these early flights. It's not that I'm ballsy. Normally I'm conservative on CG location, but chose it for this model based on my profile bomarc which is the same size, It was too heavy to try glide flights. However it actually requires a slightly more nose heavy CG location for boost than the profile model.
 
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burkefj

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Had a beautiful morning so went over to George Rachor's secret launch facility off the baltic coast and flew my New bomarc on Estes E-12-0's with the end plugged....Beautiful flights, dead nuts straight, hands off boost, not quite as high as an E-12 aerotech motor since the total impulse is lower, but very nice and nice glide and landings, here is the last flight, so far absolutely no issues landing on the pods, even on soggy grass.

[video=youtube;_OPaA993hcM]https://www.youtube.com/watch?v=_OPaA993hcM[/video]
 

burkefj

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At one of the tri-cities launch a gentleman walked up and gave me two of the old aerotech E-15 motors designed for the SR-71 hobbylab kit so I took out my bomarc and flew them. Was a bit windy but handled it well, here is the first flight.

[video=youtube;orFdH6xyaJM]http://www.youtube.com/watch?v=orFdH6xyaJM&feature=youtu.be[/video]
Frank
 
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RocketFeller

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I saw this fly yesterday (along with a dozen flights of all sorts of cool gliders) and it flew beautifully. While everyone else was losing their rockets in the tall grass/oats Frank would just fly his in and land them a few feet away in the tall grass. He made it look way too easy...

I think I am 2/3 of the way towards convincing my wife that I need to get an RC controller for Father's Day. If only she hadn't seen the sale going on for Traeger grills.
 

TopRamen

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Wow! That thing is impressive and then some, and then some more!
Amazing. :clap:
 

burkefj

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Its, not as forgiving on landing, wasn't sure of interest and probability of people being able to fly it well enough to not kill it.
I'm going to sell a couple of beta kits and see how people do.

Frank

Frank, is this a kit?
 
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