RC Rocket Glider X-15 Project

[retro]

This is my latest endeavor into RC rocket gliders. An all composite (No cardboard or plastic in this model) X-15. The X-15 flies on an Aerotech I200W with two E-25 air starts. I used water ballast in the nose cone to shift the CG towards the CP (NP term for glide) to maintain excellent vertical stability then transitions to glide mode. Glides back under RC pilot control to around 400' ft AGL at which pilot deploys two large chutes to bring it in nice and easy close to the launch location. Uses Jomar switches to activate air starts and parachute deployment.

Hooked up a servo to a plastic water hose shut off valve to dump the water ballast. Dumps four cups of water in six seconds.

Its a real hand full to fly only allows a few seconds to trim. One flight so far lost control on glide phase and popped the chutes to recover. Needs CG shifted further back I had it up forewards on first flight to allow for stability margin. Now I'll tweak it further aft with each flight until I find a suitable elevator response.


Check it out at:


https://www.retroflight.com/XPROJECTS.html

 

[KenParker]

Now that is really cool.

 

[Stymye]

impressive ! and nice work using composites

I would like to hear more about your construction technique !

 

[retro]

Thanks,

Construction: (Very) Condensed form

Step) CAD two designs (one for the plug and one for final model).

Step 2) fabricate a plug for the mold. I use CNC laser cut formers attached every 2-3 inchs to a center 1" square metal tube. Attach 1/8 sq balsa stringers. Cover with 1" balsa strips (some are soaked). Cover with 6 oz then 2oz fiberglass and epoxy. Spray with Nelson's filler then water sand to 1500 grit.

Step 3) Laser cut parting board from CAD files. Then apply release wax (six coats) and release agent. Lay up top side of mold with fiberglass. Flip over lay-up opposite side of mold. After cure split mold remove plug with molded in water jets, water pressure.

Step 4) Wax the mold halves, spray with nelson's primer, lay in fiberglass, carbon, kevlar cloth and epoxy resin in each half mold. No kevlar in cut out areas only fiberglass. Oven cure at 180 degrees for three hours.

Step 5) Epoxy hard to reach bulkheads and formers is one half of mold. Connect mold halves. Apply 1" wide 6oz fiberglass cloth and epoxy along ID of mold seam lines. Let cure then separate mold halves, hook to garden hose and use molded in water jet spray to pop fuselage out of mold.

Step 6) CNC wire foam wing cores. Spray Nelson's primer onto plastic release sheets. Layup carbon, kevlar, fiberglass and epoxy skins onto sheet. Wrap sheet around wing core and place into foam wing craddles along with breather material. place into vacuum bag and oven. Apply vacuum then heat to cure (not to hotwith foam cores) 120 degrees.

Step 7) Add additional formers and buldheads through hatch. Apply desired finish. I use Nelson paint products.

Yes its a lot of work but it yields an extremely light weight yet strong durable model. And with the molds you can make more parts if needed. Before you tackle a project like this you need to hone your composite molding skills on smaller projects. Lots of how to video's etc... out there to help you out.

 

[KenParker]

CAD? Laser cut? Man, you must have a shop that is the envy of every guy in town.

Where do you get Nelson paint products? Is it lacquer? Enamel? Acrylic? Latex? Urethane?

 

[retro]

I'm an Engineer by trade so yes I have a high end CAD program (AutoCad 2000). However there are several low end CAD programs that would suffice for model design. AutoCAD is overkill its what I have so Ii use it. Actually Rocksim7 can generate the fin, formers, bulheads for CNC laser cutting shops. Rocksim7 also generates a CAD drawing and 3D as well for around $100 its a steal. I send my CAD files out to local (in state) laer cutting shop.
Three days later I have all my parts cut to exacting size for a very reasonable cost. The CNC wire foam cutterI made myself from plans that I downloaded from the web. Here's the where to go for Nelson Paint. I love this paint, its sprays on easy, dries super fast, non toxic, light weight and is very durable. I shoot with a touch up gun.

https://www.nelsonhobby.com/paint.html

Spaceman's Luck,

Doug Gard

 

[GL-P]

I'm jealous!!!

 

[eugenefl]

Wow...outstanding work! Welcome to TRF. Your kind is a rare breed built on patience, attention to detail, and certainly amongst some of the most skilled builders in rocketry. Nice craftsmanship and thanks for sharing your X-15 project.

 

[retro]

Well if the model makes you jealous. . .do I dare to mention the rush of holding the transmitter? I'm talking total interactive rocketry now from the second the motor lights until it touches the ground again. RC rocket gliders are a real rush and with air start its even more exciting. Its like living in sloooow motion during the whole flight I'm glad to have the parachute back up, without it the model wouldn't have survived its maiden flight. I tie a bright orange stremer onto the parachute ejection transmitter stick, that way I can find it in a hurry and I'm carefull not to it by accident in all of the excitment.

Yes the carbon was expensive, I only use the cloth in strategic areas the rest of model receives a layer of carbon mat. . .much cheaper but still adds tremendous rigidity.

 

[powderburner]

Retro,
That looks like very nice work.
Where did you get your aircraft geometry data? Did you go for 'simple' versus 'scale' to simplify the design anywhere? (It looks like you left off the canopy brow ridge)
That parachute business definitely looks like the smart way to go! It would be just a bit too hairy to try to deploy skids on the rear of that model and slide it onto a smooth patch of . . . maybe you could borrow a highway for a few minutes?

 

[retro]

Thanks,

Its near scale, I fudged in a few areas I was merely going for a representation. I increased the wing area quite a bit, while maintianing the same wing dimensions only enlarging them. I did this in order to achieve a bare minium of acceptable wing lift to weight ratio for glide that is closer to a controled dive (nose down at around 30 degrees).

I used Aerofax Datagraph #2 (North American X-15/x-15A-2)
for reference.

https://www.ninfinger.org/~sven/models/bibliography/x15.jpg

See Aerofax Inc:
Paperback (1988) Out of Print
Aerofax Inc.; ASIN: 094254840X

 

[retro]

Whoops!

Wrong ISBN # (thats the X-1) book number.

should be:
Paperback (June 1986) Out of Print
Aerofax Inc.; ISBN: 0942548345

PS

Not many rocket launch sites come equiped with paved landing strips.
I design parachutes into all of my RC RG's. Glide back close to the launch area then pop the chutes and let the model drift in the last few hundred feet. I have added retracts to some models and the 1/4 scale RC RG ME163 model that I'm designing now will belly land like the original on a carbon, kevlar, reinforced teflon strip pad.

 

[shrox]

The SHX-15B is just screaming for R/C conversion I'll bet...

 

[retro]

Shrox,

Found your web site. . .awesome graphics and the DYNA model rockets designs are excellant. However the SHX-15B model I couldn't find a pic of it? I found a pic of the of the fin set design. Perhaps I've been breathing to many NOX fumes. Now that you've evoked my curiosity can you direct me to a picture of the SHX-15B????

Should I ever decide to upgrade the graphics on my web site beyond my humble attempts you'll be the first person I contact!

 

[OKTurbo]

https://www.rocketryforum.com/showthread.php?s=&threadid=8656

This link is to Shrox's thread on the SHX-15B.

I am blown away by your R/C model of the X-15. First Class stuff....

John

 

[retro]

Alright I found a pic of your delta SHX-15.

The X-15A2 follow on delta wing concept version would make a much better RC RG than the standard trapezoid strake wing X-15. More wing area, better wing loading and more forgiving of the CG shift. If I were to build and market a large-scale composite X-15 RC RG kit it would be the delta wing version.

I like the chiseled lines of your SHX-15 delta version and the white paint scheme looks nice. It would make an excellent base for a micro reciever pack mid sized RC RG.

 

[brianc]

Originally posted by Retro
Now that you've evoked my curiosity can you direct me to a picture of the SHX-15B????

Here's a liftoff shot of mine (still missing decals) from another thread.

https://rocketryforum.com/attachment.php?s=&postid=140151

 

[Mike]

Wow....fantastic stuff. I have a SpaceCraft X-15A-2 thats just waiting for Spring and it's maiden flight.

 

[retro]

Nice pic.

I can see why this model is in demand. How does it compare to the Estes X-15 as far as size is concerned. From the few pics I've seen its sexier than the standard X-15 very sharp lines. It reminds me somewhat of the NASA X-15 early design.

 

[powderburner]

Small world, Retro---

I went to school in Ames, graduated in '75. I know someone in the House (Helser Hall, Fulmer House, now torn down) was from Atlantic but I couldn't remember who it was to save my tail.

Just in case I can't locate a copy of that Datagraph, I might ask to borrow or rent yours. My copy is long lost, and I have been looking around work for anyone else's to borrow (you'd think with a couple thousand airplane-heads hangin around that you might be able to find a copy of that book?).

I am working on a 'lines' model of the X-15 (been at it off-n-on for more than a year). So far I have had pretty good luck with finding aero surface geometry and basic fuselage geometry, well documented in NASA sources. I am currently working some leads to pin down more of the details of the side fairings and the canopy. I am hoping to collect enough data to fully define the contours for a nice scale model.

It probably is quite necessary to scale up the wing area to achieve any sort of glide performance. Sounds like your model has a glide slope that is just about 'scale'?

 

[shrox]

I called it the SHX-15B because it is not a scale model, the nosecone in a little long to be scale. It is pretty close though, and looks good. It is based on the Apogee PNC-70 nosecone and body tube.

 

[retro]

>Mike:
>Wow....fantastic stuff. I have a SpaceCraft X-15A-2 thats just >waiting for Spring and it's maiden flight.

Yes with winter closing it looks like flying is over until spring.

>Powderburner:
>I went to school in Ames
WOW! I went to school in Ames also. Actually lived in Ames for 13 years (cool city Ames).

>I am working on a 'lines' model of the X-15
Seems like the X-15 is very popular with modlers! Its always been one of my favorites and still is. Ever see the eatly 60's X-15 movie with Charles Bronson? I have a VHS copy that I obtained from an undisclosed source. Great movie for X-15 fans almost like a documentary (but boring for anyone else). Lots of X-15 footage.
https://www.moviesunlimited.com/musite/product.asp?sku=D48581++