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Radio Control Forum => Stick and Tissue R/C => Topic started by: Sundance12 on January 14, 2011, 02:12:33 PM



Title: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 14, 2011, 02:12:33 PM
Ok now this project is going to be an interesting one, an OV-10 Bronco rubber power twin but directed with a 3 channel RC system for guidance.

I have the option of making the front ends electric power as well but initially I will be leaving the power system as Rubber Twin and adding the RC system for control. This airplane is traditional stick and tissue construction leaving it as traditional as possible making only the mods for the movable surfaces and the installation of the Falcon Micro RC system.

First up is the center fuselage, and cockpit area. My biggest reservation for this project is the large canopy. I have not the tools to mold one. But that never really stopped me. I will make a simple vacuum former for this canopy as time goes on from the great info found elsewhere on the forum.

This fuselage is nothing special, only 1/8th stick box with the foam front and rear cones. However, I hate foam and will be doing the nose and tail-cones up in balsa frame and sheet.

The part of construction that drives me nuts is cross bracing and getting it all square. There are great tutorials on making this process go well but do I read them... Nooo, I just go ahead and suffer through the construction in any way that works.

So, now that I have started, I have to Finish...

Cheers

Bruce F.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: dputt7 on January 14, 2011, 05:57:45 PM
Bruce
WOW! I'm not a fan of foam or R/C but this has my interest. What size is it? What plan are you using?

Best of luck,
Dave


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 14, 2011, 07:19:58 PM
Hi Dave

I am building from the Model Builders Plan by Tom Houle, 36 inch span. 234 Sq In.

Well you are the same as me, I prefer other disciplines like free flight and C/L but I wanted to make this special and marry traditional Stick and Tissue builds and some control of the airplane instead of release my art to flying away.

So this is a test, I think that since this radio is so small and the plane is so large the performance will hardly suffer from a normal FF flight profile other than I will have some control over it's overall flight pattern and return to earth than roll the dice with some kind of ancient DT system.

I know that I am going to ruffle a few feather in the purist camps...

grin

Bruce F.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Pit on January 14, 2011, 07:47:32 PM
VEEERY INTERESTING! I suppose the plan is available from Bill Northrup? Do you remember what issue it appeared in? I built an RC version for twin .40-.60's from a German FMT plan about 25-30 years ago - good flyer till the inboard motor cut out on the turn to final (no glo-drivers then).

I've got a 2.4 VAPOR unit looking for a home.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 14, 2011, 10:35:16 PM
Hi Pit

See a PM to you.
In the meantime, the plan is from Model Builder:

OV-10A BRONCO - FF RUB SCALE PG 66 10-98 MAR 1980 MB

Cheers

Bruce F.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: dputt7 on January 15, 2011, 12:47:29 AM
Hi Bruce

Does this mean you can run very little down thrust and control the climb with elevator to really get some height? I have a mate that had an R/C version painted as a Fire Controller that was neat. Guess you have finished all that research there is a heap on the net. While looking for this photo I found a photo of a turbo prop Tracker. Oh well another for my todo list.

Regards Dave


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: lemuel on January 15, 2011, 04:56:18 AM
Wow Rc twin rubber! now your talking!! actuators would be super light.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: DaddyO on January 15, 2011, 05:05:33 AM
What about using 'muscle wire'....

Paul

ps
Lurve the Bronco - one of my favourite twins


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Pit on January 15, 2011, 09:05:59 AM
and LOTS of room for a long motor.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 15, 2011, 09:30:39 AM
Well the RC system is hardly heavy,
Servo is 1.6 Grams,
Receiver is 1.5 Grams.
Battery is 3.4 Grams

So three servos, receiver and battery and wires to run it all is only 12 grams or so...

In this airplane, at a wing size of 234 sq in, I don't think that this radio system is hardly going to be a concern. This is not a small plane and with twin rubber motors, power is not going to be a problem. These servos have plenty of movement for normal flight movements, and I am not an aerobatic flier, so control for launching, cruising and thermal-ling and then return is easily achieved. I will be able to have the downthrust set for zero which is indicated on the plan and there is a little of Right Hand and Left Hand thrust arrangements on the plan for that. As for climb I will be able to control the elevator for climb and then glide phases so A RC setting for Free Climb, and then a RC setting for Free Glide and rudder and aileron control for directional steering and approach and landing. To be specific, this is really a RC assist Free Flight airplane, in replace of any other kind of DT system. I don't really know what all the fuss is about operating a Rubber power plane with a RC system... Grin Ya Lots of room for two long motors...

Colors are still not decided upon, I will cover it in tissue and use Varathane Diamond Wood Finish for a sealer. No landing gear, perhaps plug in for show.

I considered muscle wire, many months ago. First it's control movement is short, this is a big plane at 234 sq in of wing and there is more room for these little servos that I don't need to go so minimal. Plus, I have the servos already.

Servos;
The Ubiquitous Falcon 1.6g Servo has now been further improved and is compatible with all radios including the new Spektrum 2.4GHz radio. It has unique electronic stops and it will not arm until it receives a constant input signal. Innovative design developed and manufactured in the UK. Fast and powerful

Receiver;
Falcon Receiver with DSP & Fail Safe
Falcon Receiver Mk III with DSP & Fail Safe
35 MHz & 72 MHz IDC

Battery:
Lithium Polymer 130mAh 3.4g
4th Generation Li Poly cells. 10c continuous discharge.
25mm x 19.9mm x 4.7mm
Supplied as standard with tags


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Pit on January 15, 2011, 10:10:01 AM
Ja, Spectrum has a relatively new ulta micro-light AR6400 with two of those servos built onto the board (brick) that only weighs 3.5 grams. Even has the ESC built in (which u WON'T need with gummi motors ;D). Not too expensive so I Bought one with my tranny conversion kit.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 15, 2011, 10:27:59 AM
There are many small RC systems that would do the job Pit, no problem there. The micro RC system has come of age and we can still use the building techniques that we enjoy to use this micro stuff. There are some others on the forum that have used these small systems to good effect.

I have completed the tail cone, and somehow make it as complicated as possible. It is made up of sheet wood and triangle stock which came out fairly light but not without much work. I still prefer wood over foam...

Now for the Nosecone and forward section dashboard area.

Bruce F.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 15, 2011, 07:07:44 PM
Nose Cone and dashboard formers

The nose cone is complete and came out ok. It's light, and solid, and I think I got the proper shape. These carving projects are not for beginners, they take time and you can always over do it but cutting or sanding too much. The thing I have learned about balsa is that you can re apply balsa back onto or into areas that you shaved or cut off too much. This nose cone was made from a number of layers of block and sheet wood laminated together. But as always, while carving out the inside with the Dremel Tool I cut too much out and ended up going through to the outer surface. So some scrap wood and CA glue and bond, then sand and presto, problem disappears. Well, it's still there but no one will find it.

The overall central fuselage is taking shape and I will sheet up the dashboard deck with some 1/32 sheet and think about just how I am going to create a canopy in a painless way...

Cheers


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: tom arnold on January 15, 2011, 07:48:43 PM
Great project, Bruce, I have not seen an OV-10 of any size that did not fly like gangbusters. I think the canopy forming is going to be a non-event, though, as I have done one that size and it was pretty quick. My approach to canopies is to staple a sheet of plastic to a couple of flat sticks on the left and right edges, hold it over a stove unit and then pull down over the carved form on a stick. You have to bring your hands together after the draping underneath the form and hold it as it all cools such that the canopy develops that "under curve". Straight plunge forming won't do that and I am still too lazy to make a vacuform rig. I also did it in 2 shots----one for the windscreen alone and a second for the long bubble canopy.

I finally did make a couple of spiked flat sticks that I use and reuse with all sorts of canopies. The "R" stands for Right Side pair. You squeeze them together on the edge of the sheet. Just a thought as I know there are lots of ways to do it.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 15, 2011, 08:25:05 PM
Hi Tom

Thanks for the vote of confidence, I think that you have good tips and that gives me some ideas to consider. I have been dreading the whole vacuum box project. I will have to document my experiences.

Cheers<


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 15, 2011, 10:45:39 PM
Completed Nose Cone and Dashboard Section.

For now, the nose is done which includes the dashboard. This section was just former and sheet construction which went together fairly easily. The nose cone was attached and sanded to shape with the dashboard. Also attached and sanded to shape was the boat tail aft cone, and some final sanding took place. I am pleased with this construction so far.

Cheers


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Wout Moerman on January 16, 2011, 03:48:15 AM
This is a very cool project, and I am sure it will work great. I am on the same track, building a 54" Taylorcraft which will be rubber powered RC. My components are a lot heavier, about 25 grams, but I hope most of it will be used as functional ballast.

Wout


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 16, 2011, 08:23:02 AM
Hi Wout

Glad to hear that you are trying the same discipline. I think that you will have little trouble with that project and a heavier system, that is a pretty big wing to carry it all. Good job. I think that the weight of batteries, being so little now is really the cross over point where rubber power RC becomes viable.

I think that there is lots of power in Rubber and so this becomes a test project to see what I can get away with. Certainly a Twin Power will give me the reserves to haul around an extra 12 grams of radio.

You will have to start a thread on your Taylorcraft Rubber Power RC.

Cheers


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 23, 2011, 03:00:39 PM
Canopy Plug

This took a while and tested my abilities in carving and forming. The plug for the canopy came out ok, still some filling and sealing with some kind of sealant, perhaps diamond cote varathane. This mold is made from a box, then laminated to size and then carved. I did not use much block other than up front.

The issue is to make a form box, plunge mold it or something else. Have to decide which, it'a a long and high canopy and a small forming box will not likely work.

Bruce F.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Wout Moerman on January 24, 2011, 03:44:16 AM
Bruce, i read a method a few days ago which could be useful. I don't remember if it was here or on SFA. The mold is placed on a long stick which is clamped to a rigid object. The clear plastic is nailed on two wooden handles, so only 2 sides of the plastic are supported. The plastic is heated and pulled over the mold while the handles are moved towards each other. I think this will work well for this shape.

Wout


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on January 24, 2011, 07:52:35 PM
OK Wout

I will try this method first, and see how that works out, I have all the components for this procedure. Will have a report soon.

BF


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Wout Moerman on January 25, 2011, 03:09:13 AM
Bruce, I remembered where I read about this method. It was in reply #13 of this thread :-)
Good luck in trying!


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Wout Moerman on January 27, 2011, 08:50:03 AM
Bruce, I tried the technique a few days ago and it worked perfectly on a big canopy mold of one of my club members. The mold was on top of a 6 inch piece of wood which was clamped in a vice. I heated a sheet, about legal paper sized, above a electric stove. I held the plastic in my bare hands, without a wooden frame. Then I moved it quickly over the mold and pulled the plastic over it. The result was a nice clear canopy.

Highly recommended


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: dosco on March 23, 2011, 04:30:31 PM
What's the status of this most interesting project?


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on March 23, 2011, 09:33:56 PM
I am stuck on the canopy forming process, just sandbagged...
I have the plastic I need, I have the canopy carved and it has some finish on it to make it smooth but I am without the forming method. There have been some good suggestions and the  plunge method is the one that I am moving towards. This is a big form and I am just going to "get over it" and take a shot on some tests. 

I will keep you posted.

Cheers
Bruce F.


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: dputt7 on March 24, 2011, 02:30:11 AM
Bruce,
If you can find a cool drink bottle (soda pop ?) large enough cut off one end and fit the mold into it and apply even heat with a heat gun or probably even a hair dryer, the PEP bottle will shrink down and form around the mold. You will then have to cut the bottom away to remove the mold. Make sure your mold is strong or it may collapse.

Regards Dave


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: keven64 on November 20, 2011, 01:48:36 PM
Hello Bruce,

I just joined here.
I had a coincidental 'double-link' - where a page at the Vintage Plans thread ( on RCGROUPS ;) ) included a link to this forum...
...and also a search for "Bronco twin plans" included a link to this thread.

So - here I am !

I have four Spektrum AR6400 receivers and two AR63000 receivers ( with appropriate tiny servos ) - and I cannot make up my mind which to use for a Bronco - and what small size to go for.
Electric powered - though...

Can I ask what flight times you expect to get with a such rubber powered R/C model ?

Keven. :)


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on November 20, 2011, 02:27:28 PM
Hi Keven,

I am using a receiver from Falcon RC, it's pretty small and so weight will be the least of my concerns. I suspect that the running time for this model will be less than a minute under power if I operating using typical rubber power setups. However, I am having a change of heart and may still make this plane ito twin electric, which is way more logical. there is plenty of wing on ths plane to cary it all...

To be determined.

Sundance12


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: keven64 on November 20, 2011, 04:20:34 PM
...Yeah - I know the Falcon receivers are lightweight and tiny.
I was not 'challenging' the radio weight issue.

I wondering about 'power-on' times with rubber power. ;)
It's a long time since I made anything that had rubber for power... one of the last I made ( in the mid-80's ! ) had a free-wheeling propeller with variable pitch.
Nothing 'clever' - own-design simplicity stuff, with 'eyeballed' pitch adjustment - for each blade...

My memory is terrible - and so I cannot recall exactly what I did when trying to play about with extending 'power-on' times - using the torque curve against pitch.

That has me wondering again about such a model as you conceived here ( rubber-powered R/C )... but with a single propeller with provision for variable pitch... and possibly - also diameter !

I have an old Aeromodeller annual that features a rubber powered single-channel R/C model from Japan, and I have often thought about how well that would now work well - with two functions and modern radio.

Electric is a far easier option, though, I think - with a twin.

Keven. :)


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on November 20, 2011, 07:00:55 PM

Well, there are not that many examples of rubber power RC out there so it's a field that is wide open for much experimentation. I was figuring that a good power climb to some altitude and then directed flight back is all that I would get. Perhaps some prolonged cruise portion of the flight. Certainly a variable pitch prop on the power would be some advantage to increase the run time. Electric power is the easy way out as much have been developed for small powerplants. The age of electrics has arrived for sure.

I agree with your sentiment, that this plane is really suited for electric flight and may get a new plan...

Bruce F.



...Yeah - I know the Falcon receivers are lightweight and tiny.
I was not 'challenging' the radio weight issue.

I wondering about 'power-on' times with rubber power. ;)
It's a long time since I made anything that had rubber for power... one of the last I made ( in the mid-80's ! ) had a free-wheeling propeller with variable pitch.
Nothing 'clever' - own-design simplicity stuff, with 'eyeballed' pitch adjustment - for each blade...

My memory is terrible - and so I cannot recall exactly what I did when trying to play about with extending 'power-on' times - using the torque curve against pitch.

That has me wondering again about such a model as you conceived here ( rubber-powered R/C )... but with a single propeller with provision for variable pitch... and possibly - also diameter !

I have an old Aeromodeller annual that features a rubber powered single-channel R/C model from Japan, and I have often thought about how well that would now work well - with two functions and modern radio.

Electric is a far easier option, though, I think - with a twin.

Keven. :)



Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: crashcaley on November 20, 2011, 07:23:42 PM
Bruce, What a neato project.  I've heard of RC assist for rubber powered models.  Never seen one though.  Now I will.   :)
  When in the US Air Force, one of my first duties was cammunications support for O-1 Birddogs and O-2 SkyPigs.  But right next door was my counterpart who supported the OV-10 Bronco.  Quite an airplane.  Very fast and versitile.  Caley


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on November 20, 2011, 07:47:11 PM
Bruce, What a neato project.  I've heard of RC assist for rubber powered models.  Never seen one though.  Now I will.   :)
  When in the US Air Force, one of my first duties was communications support for O-1 Birddogs and O-2 SkyPigs.  But right next door was my counterpart who supported the OV-10 Bronco.  Quite an airplane.  Very fast and versitile.  Caley

Hi Caley

Thanks for the moral support, and I need it as this project is an ambitious one for me and I get sandbagged on it like now. The canopy work is especially taxing my abilities and I may have to farm that out to a friend of mine who does these big canopies better than I.

What communications did you do there, then? 

It is quite an airplane and a fine project for anyone.

Cheers

Bruce


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: crashcaley on November 20, 2011, 08:33:34 PM
Bruce, You certainly did choose a good subject and a very challenging one.  But I know it will be a good flyer, especially with the little extra help you can give it with the RC system, when it needs it.
  There, as in the US Air Force, or with the O-2 and O-2 airplanes?  The later was UHF/VHF/HF/AM voice comm support.  But I put together their comm package for each mission, and briefed them on it.
  Look forward to seeing your progress.  Caley
 


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on November 20, 2011, 09:44:44 PM
Bruce, You certainly did choose a good subject and a very challenging one.  But I know it will be a good flyer, especially with the little extra help you can give it with the RC system, when it needs it.
  There, as in the US Air Force, or with the O-2 and O-2 airplanes?  The later was UHF/VHF/HF/AM voice comm support.  But I put together their comm package for each mission, and briefed them on it.
  Look forward to seeing your progress.  Caley
 

Interesting, comms work, I am a amateur radio operator and have a home station here in the workshop. VHF 2M/ HF 80M 40M, 20 15 and 10 meters. For round the world communications. Many times, while building I am listenting to converstations from overseas, Europe, US, Canada, Japan, Australia. I have 3 antennas in the yard that receive and transmit up to 500 watts. Anyway I won't hijack my own thread. We can chat coms somewhere else...

Bruce

VE4BDF
Shoeless Communications
http://www.qrz.com/db/VE4BDF



Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Daithi on November 20, 2011, 10:10:05 PM
I've Oz on 30 and 17 Bruce and NZ on 30 ;) (I've also India, Sri Lanka, Japan and China (mainland) and I never go over 50 Watts  :D )

73 de Daithi, GI7OMY

http://www.qrz.com/db/gi7omy


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Don McLellan on November 21, 2011, 12:24:15 AM
Hi Bruce,

I was wondering what happened to your model.  It has sort of been off the 'air ways' for some time. 

Also, I think this is a very cool airplane and rubber powered RC.......... well, I gotta try this one of these days.

Don (waiting for more progress and posts)



Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: keven64 on November 21, 2011, 08:09:06 AM
I gave over with rubber power in '85 - haven't bothered with it at all since. :-[

Instead, I concentrated again on making R/C models - with the 'new challenge' of with electric power - using motors and 6-cell batteries 'borrowed' from my Tamiya buggies !
My first 72" powered glider registered only 64db on the clubs noise meter - in 1986. ;D

I think I might have a go at making a similar size Bronco as this - though I'll draw my own plan.
Now to decide on which motors to use...

Keven. :)



Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: sparkle on November 25, 2011, 06:18:40 AM
 ;D  looking forward to seeing this project take shape!


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on December 26, 2011, 06:11:19 PM
Ok some progress on this project, and by far the most challenging. Canopy work, using the suggestions from the members here, I plung moulded the canopy. It was done in parts and sections as this was such a big canopy it could not be done all in one go. I had to form portions of it one at a time. Top, front and two sides. Then formed the canopy rails and rings in the normal way as per plan of 4 layers of 1/32 wet soaked and wraped on forms to dry over nite. Then building the canopy rails and adding plastic canopy sections to that. I am not so impressed with the effort but it will turn out better once detail and covering are going to be applied over all rail areas. I will look much better once it's all dressed up and detailed.



Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: crashcaley on December 26, 2011, 06:54:58 PM
Bruce,  I certainly would be very proud of such intricate work.  Great problem solving and great work.  Caley


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Don McLellan on December 26, 2011, 07:01:01 PM
Looking good Bruce.  Nice work.

Don


Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Sundance12 on December 26, 2011, 07:56:55 PM
Looking good Bruce.  Nice work.

Don

Thanks Don, thanks Caley, it's these kinds of projects that push your limits of model building for the better. Even if one is not 100% satisfied with the result, one has to respect that fact that they have acieved their goal and be happy that it is a new step. This project is far from over, it is a big challenge for me as I am not building completely to the plan. I have made from balsa those parts that were specified as foam and I like working in wood most of all, so onward. Next steps some easy stuff like tail sections or fuselage booms.

Cheers



Title: Re: OV-10 Bronco Twin Rubber Power RC -Build-
Post by: Art356A on March 09, 2016, 01:37:48 PM
The Twin Tail Terror Lives!!

http://www.thedailybeast.com/articles/2016/03/09/why-is-america-using-these-antique-planes-to-fight-isis.html