R/C RBG build thread

[FlyBack]

Description:

This model is loosely based on a Lockheed design study for a two stage to orbit (TSTO), reusable space transportation system done in the late sixties. It consisted of a Carrier Vehicle and Orbiter stack that sled-launched. The Carrier Vehicle had air breathing engines for recovery and horizontal landing. The Orbiter was also to be recovered to a runway.

I’m designing it to be flyable in three different configurations. Configuration 1 is being built now and will be covered in this thread. Configuration 2 was built in 1986, flown once, crashed, then rebuilt partially and never flown again. It boosted perfectly but failed to separate and augured in. The separation problem has been fixed. Configuration 3 will be built from tooling and templates I’ve already completed for Configuration 1 and will be covered in a new thread (probably next year at the rate I’m going).

Config 1 - R/c Orbiter glider / Rear ejection, parachute recovery Booster.
Power: Quest D5-P in the Orbiter. Estes E9-4 in the Booster.

Config 2 - Free flight Orbiter glider / R/c Carrier Vehicle glider.
Power: To be determined… the motors used in the original are OOP. The Orbiter motor ejected with streamer recovery and I’m not sure I want to do it that way this time around.

Config 3 - R/c Orbiter glider / R/c Carrier Vehicle glider.
Power: Aerotech E6-RCT in the Obiter. Aerotech G12-RCT in the Carrier Vehicle


More photos to come… but for now, enjoy these. Later, if there is enough interest, full specs and drawings can be made available (after, and only after it has successfully flown again of course).

Regards,


FlyBack

 

[jj94]

Very nice. I'd like to see some more pics.

 

[FlyBack]

More photos of Config 1 with the Aerotech 24mm and 32mm RMS R/C motors. This configuration would actually use the D5 and E9. However, since the same tooling is used for all versions I built this mockup with the larger motors. Doing it that way helps me work out the thrust line geometry for the worst case first.

Regards,

FlyBack

 

[rokitflite]

As my first official post now that I have FINALLY been able to log back in... This thing looks cool as heck and I want constant updates and flight reports!!! Great job!!!

 

[MaxQ]

Very Cool...do you plan on firing the motors in tandem or sequentially

Looks like you'll ultimately need two guys flying it with adequate seperation of frequencies...what radios do you use?

More pictures as you test it!

 

[FlyBack]

Finally settled on motors and R/c gear and have frozen the design for Config1. Long story short... the recent appearance of the Quest D-5 motors and the two gram Spektrum 2.4 ghz receivers has made this a much simpler model than two years ago. The design at that time required a timer activated ejection charge for the chute, larger motors, and heavier R/c gear. Seems like I've been working on this forever... Why is it that when you have the time you don't have any money, and when you have the money you have no time?

MaxQ:

The motors fire in tandem and require a hold-back.

Yes, Config3 will need two pilots. Frequency separation is handled by both using Spektrum 2.4ghz transmitters.

BTW, The glider in the attached photos flies. It has survived a number of hand tosses and has allowed me to really dial in the C.G. and elevon deflections. The mock up phase is over.

Regards,

FlyBack

 

[AKPilot]

This is cool as heck! Great job!!!

 

[FlyBack]

-deleted due to naming conflict-

 

[rokitflite]

Wow, cool... I just ordered a couple of those AR6300 receivers. I had missed those!

 

[kjohnson]

Cool project.

I've used the non micro-jst versions of these servos and was unimpressed by the strength and torque provided by the gear train. Hope they will stand up to what you will be throwing at them.


kj

 

[delta22]

Very cool project.

Looking forward to flight pictures and video.

I have built a few rockets, but just getting started with RC.

The Spektrum gear is very interesting. Does the choice of receiver limit the servos that can be used?
Is it an issue of how much power the rx can supply the servos?
Is it possible to use a small receiver with mid sized servos?

 

[BB-ROCK]

Nice work, can't wait to see it finish.

 

[rokitflite]

Is it possible to use a small receiver with mid sized servos?

Yes, but you would need a higher voltage & amperage battery pack for larger sized servos... Flyback could use slightly stronger ones without a problem with that 130mah battery... I used the ones hes using with a 7.4V 60mah pack... And like Kjohnson said... Becareful, they are kinda whimpy. Mine were only moving 2 1/2" x 1/2" control surfaces.

 

[FlyBack]

Cool project.

I've used the non micro-jst versions of these servos and was unimpressed by the strength and torque provided by the gear train. Hope they will stand up to what you will be throwing at them.


kj

Thanks KJ

Actually, that is a concern of mine. I hope to deal with it in several ways. Number one is by keeping launch acceleration below 5g and max velocity under 144 fps. Control rods will be .020 titanium wire and kept as short as possible. Control deflections will be quite small and the surfaces are small. If necessary, I can wedge them in place against the Carrier Vehicle flaps and do a hands off boost. The controls would then only be free after separation (which occurs at about 45 fps). That worked OK for the Config 2 prototype.

Plan B would be to use the 3.4gram servos which I have had good results with in an ECEE Thunder conversion (photo attached). Delta22, that thread has a lot of info you may find useful (trying not to hijack my own thread).

Regards,

FlyBack

photo credit: NHRC member D. Laney

 

[rokitflite]

Hey Flyback?
I got my receivers today and I have a question... Have you been able to find any SERVOS that will work correctly on 3.7 volts? All of the micro ones I see and have say 4.8-6 volts. Even the ones they sell with the receiver in the flight pack say 4.8-6. If the higher voltage servos DO manage to work, I would guess that the torque would be pitiful.

-Scott

 

[cussler08]

This is too freaking cool. Any further info will be appreciated! Brilliant!

 

[FlyBack]

Hey Flyback?
... Have you been able to find any SERVOS that will work correctly on 3.7 volts? ...

-Scott

Rokit

I have used the Blue Arrow 3.6 and 4.3 servos and the Dymond D47's with a Spektrum AR6100 receiver on a single cell lipo. Based on the info sheet that comes with the BA-TS-2.5 servos they seem to be good for 3-6v (although I haven't tested them yet).

There is a bigger issue I have found with the smaller Spektrum receivers. On the rcgroups.com forums there is a lot of chatter about them loosing signal lock below about 3.5v while the servos are under high load (search Spektrum and brown out). Just to be on the safe side I have switched to using a small voltage regulator and two cells. Also, you are right about the 60ma batteries... I use the 135ma size for ballast more than amp capacity.

cussler08- Thanks. Been working on my launch rail this week but should get back to the model soon.

Regards,

FlyBack

 

[FROB]

That IS very very cool....
about the battery issue,
I am very surprised that there doesn't seem to be much RC radio gear optimized for the 2.5-4V range of Lithium cells yet.
You'd think there'd at least be a tiny boost voltage regulator to give you stable 5V from one, does such a thing not exist?

 

[FlyBack]

.....
You'd think there'd at least be a tiny boost voltage regulator to give you stable 5V from one, does such a thing not exist?

FROB

Ya got me thinking (a dangerous thing). It turns out they do exist... I just ordered one of these. I will now be able to test two 65ma cells (7.4v) with a 5v regulator and one 135ma cell (3.7v) with a 5v DC/DC converter (booster). It will be interesting to see which combination comes out the lightest. Will post results.

Regards

FlyBack

 

[rokitflite]

STOP POSTING THESE LINKS FLYBACK!!! I just spent $23 buying voltage boosters and servos!

 

[FlyBack]

STOP POSTING THESE LINKS FLYBACK!!! I just spent $23 buying voltage boosters and servos!

Rokit

LOL... Try and think of it as doing your part to help jump start the economy.

OR... perhaps it's time you took this quiz.

Seriously, I hope you start a build thread showing how you are gonna use all that stuff!

Regards,

FlyBack

 

[rokitflite]

Well... The shipping time from China is going to slow MY jets down a bit!

 

[FlyBack]

Well... The shipping time from China is going to slow MY jets down a bit!

When I saw the "up to 45 days for delivery" on the invoice, I kinda felt like I was getting shafted.

Soooo.... I went right out and bought an LVBoost converter from Dimension Engineering. I should have it by the end of the week.

Regards,

FlyBack

 

[rokitflite]

I got my voltage boosters from China. It took 10 days which ain't too bad in my book. They are kinda bulky. I intend to hard wire it to the receiver and get rid of some of the plugs and wires. I think it would take LESS weight to use 2 lipo batteries and a regulator, but I just had to try these little things out!

 

[burkefj]

yes, you want to watch the brown out problem, spektrum 6100's at least use more current than a normal micro fm rx. On your regulators, just be sure they are able to supply the current you need, some of the really small servos can have a high current draw under load. Are these switching voltage regulators, not a linear type of ckt?

BTW, that looks good, I like the complimentary fin design for non-assymetric drag, looks like you are using depron?

Frank

Rokit

I have used the Blue Arrow 3.6 and 4.3 servos and the Dymond D47's with a Spektrum AR6100 receiver on a single cell lipo. Based on the info sheet that comes with the BA-TS-2.5 servos they seem to be good for 3-6v (although I haven't tested them yet).

There is a bigger issue I have found with the smaller Spektrum receivers. On the rcgroups.com forums there is a lot of chatter about them loosing signal lock below about 3.5v while the servos are under high load (search Spektrum and brown out). Just to be on the safe side I have switched to using a small voltage regulator and two cells. Also, you are right about the 60ma batteries... I use the 135ma size for ballast more than amp capacity.

cussler08- Thanks. Been working on my launch rail this week but should get back to the model soon.

Regards,

FlyBack

 

[FlyBack]

... Are these switching voltage regulators, not a linear type of ckt?

BTW, that looks good, I like the complimentary fin design for non-assymetric drag, looks like you are using depron?

Frank
The LVBoost converter uses switching and I'm pretty sure the other one is linear (don't quote me on that).

The fins on the carrier/booster also steady the model on the launch rail by riding along retractable outriggers.

Back to the build...

The orbiter wing is almost finished (still have to add pre-shaped leading edges). It is a sandwich of 6mm Depron foam and 1/32 contest balsa sheet. Hard points and reinforcements are embedded prior to the whole thing getting vacuum bagged. The carrier wing is built the same way only with 1/16th sheet skin. The next part to be made will be the wing saddle (that's the white part along the side of the carrier/booster). It will be hot wire cut from 2lb polystyrene foam as a single piece. After that I can start the final assembly and mating of the two vehicles.

Regards

FlyBack

aka: DJ Miller

 

[FlyBack]

Progress report...

The wing skins are now bonded to the cores for both vehicles. The only real advantage to vacuum bagging such a simple structure is I don't have to load the table down with enormous amounts of weight.

Leading edges have been formed and cut. These are done as one piece then rip cut on a micro saw. What I wind up with is a small part from a larger, easier to handle thick sheet. Not really worried about the contour as long as it is uniform and symmetrical from left to right (well, yes I am but more on that later).


Photo 1 - vacuum bagging carrier wing

Photo 2 - making a leading edge

Photo 3 - installing a leading edge


Regards,

FlyBack

 

[FlyBack]

Mods to my launch rail are now complete (tested last weekend with the Ecee Thunder R/c RBG).

Photo - 1 - mock up on the rail

Photo - 2 - mock up on the rail (rear view)

Photo - 3 - outrigger detail

Photo - 4 - launcher and rail stowed for transport

Regards

FlyBack

 

[FlyBack]

The Quest D5-p is an odd size... 20mm. I really did'nt want to use a 24mm motor mount and ring spacers. It would just add unnecessary weight to the tail of the Orbiter glider. So... I decide to roll my own. After a great deal of experimenting with different papers, glues and wax mold releases... I found that plain old copier paper and Polycrylic works just fine. The mandrel is a 20mm glass tube from a science supplies house. A spray on mold release is used on the mandrel.

Photo - 1 - The stuff.

Photo - 2 - The setup.

Photo - 3 - Curing the part (for at least 2 days).

Regards,

FlyBack

 

[FlyBack]

Due to possible copyright infringement on the name "BlackHorse" and to avoid any intellectual property rights confusion between my design and the "BlackHorse" design concept this thread going silent. There will be no further posts by me here until I come up with a new name for the project. Sorry, I should have checked on this before I picked the name I can no longer say outloud.

Regards,

DJ Miller

aka: FlyBack