Old school OV-10

[Boots Whirlygig]

)I have the first kit version of Rich Uravichs 52" OV-10 Bronco. I have always loved this plane, and when Rich's plans appeared in Model Airplane News I thought about scratch building it. Then a few years later at the Toledo Expo they were selling the laser cut kit at the Hobby Hanger booth and I bought it. I have 2 OS25FS-R for it, but now am going to build it with electrics and have purchased a butt load of goodies from MotionRC to outfit her. I have on order a watt meter, as that's the common response from the squawk when a newbie asks questions about electrics! :(;)

For the mains I have the T45 main retracts, they are the perfect size and if you squint look scale, sort of. For the nose gear is a Super Scorpion with a 50mm wheel instead of the 45mm.

But I need advise on the motors.
I ordered what appeared to be a good match, and able to turn a 12 inch 3 blade prop, the FMS 3541-770kv and 40A ESCs, but what I received from Motion are FMS 3536-750kv. This was when I realized the motors have a strange (to me) hex on the prop shafts and don't include the motor mounts. I'm prob send them back maybe, I'm not sure they'd be powerful enough, so I ordered and received 2 FMS 3648-830kv and 65A ESCs. A beefier motor for sure. Maybe too much power? Which should I use? I want to use my 12" FMS P-38 props, cut to 11".

Theres a ScaleTech ov-10 on YouTube, which I think is based on the Uravich design, performing very good with hacker a30-1200kv turning 11/7 props, and it weighs 8 lbs!!!!
The pilot explained he added the weight to see if it could handle the xtra lbs retracts would add. It handled it!

[Alpha]

Hi Boots, I would recommend using Motocalc to arrive at a more mathematical projection of what you can expect from your proposed motor/prop combos. Motocalc outputs a wide array of information, from amp draw, static thrust, tip speed, rpm, etc. I use the program extensively in my own design projects for FlightLineRC. It minimizes guesswork and while I still recommend real world testing, I've found that the Motocalc data is generally within a reasonable range of accuracy and makes a good starting point. From there you can cater to the specific needs of your OV-10. The OV-10 has a big wing and Ultravich's airfoil is a good one. You won't need tons of power to move it along like a Bronco should.

http://www.motocalc.com/

[Boots Whirlygig]

Thanks alpha but I didn't see the application for IPhone users! Looks like a down load to a pc which I currently do not own. Looks like a useful tool to use before buying motors, I've always found it helpful to have your power system on hand while constructing a model, of course that was back working with gas planes. I know that this ov-10 could be built to fly on .15 glow and 8x5 prop, or you could add retracts, flaps and a detailed cockpit and you'd need .32 glow and 10x6 prop.
With electrics, both of these motors from MRC will spin the scale size 11x 7 3 blade prop, the smaller one on 3s, the larger 4s. I was just wondering if I was in the ballpark.

[OV10]

Hello Boots,
Back when I got my Scale Tech Bronco from Hobby Hangar(now defunct), Motion wasn't even around until 6 months later.
My motor source at that time was Exceed RC motors from Nitro Planes.
Am still using in it the Exceed Rocket Series 3015-750kV motor turning counter rotating MAS 11x7x3 props using a single 4S 4000 batt with 6 min mixed throttle management flight time.
If I had to re-motor now or in your case start from scratch, I would go with the power set up that is being used on both the FL P-38 and F7F.
The cowls that were provided in the kit where crap and I used ones made by Fiberglass Specialties.

http://www.fiberglassspecialtiesinc.com/catalog.htm

I was gonna provide a direct link to the part but see that he (Craig Schmidt) doesn't list it anymore now that Hobby Hangar is gone.
Here is his part number in case he may still have the master mold: HHR-1 and they were $35/pair.
For motor calc numbers the AUW of mine is 6.5 lbs
I didn't go with retracts at the time cause I wanted to make it earn them with it's flight worthiness.
I used these Golden Skies LG instead.

http://www.goldenskiesrc.com/SLG.html

It has absolutely earned it's worthiness but haven't done that retract mod yet because I have been kinda lazy........no actually hoping/waiting on a 60" 1/8 scale one from Flight Line( I know your listening Alpha ;))

Be glad to give any other in sight on this great bird if you so desire.
Best regards,

[Boots Whirlygig]

Thank you ov10, I was hoping to get your input! Did the Scale Tech ov10 come as a preassembled airframe without motors, and you can either use glow or electric? I ask because the airframe requirements are different for electrics vs glow. Due to the higher power impulses and vibration from glow engines, it had to be designed for glow, a compromise, and heavier than needed. I should be able to build it much lighter, maybe 6 1/2 lb with retracts!

The kit includes parts(extra balsa!) to build the optional 56" wing, the original uravich build article even recommended it, stating the longer wing doesn't detract from its scale appearance and enhances flyability. I disagree and apparently so did Scale Tech, doesn't yours have the 52" wing?

I looked up the Rocket 3015-750 (3735-750) motors in your 6 1/2lb bronco. They show it's a 3s motor, max 14.8v, 280watts, and weigh 115g. Did you try flying it on 3s? I thought for you to go 4s you'd have to use a smaller prop? The 3648-830 motors that I have are close to the power upgrade motors offered for P-38, which are 3648-880. So I should be good, right? Your input is greatly appreciated ov10!

[Boots Whirlygig]

Hey Alpha! I could sit on this OV-10 build another 20 years if MRC were to offer a Bronco in, oh, i don't, maybe 1/8 scale? Just sayin. :Straight-Face:

[OV10]

Thank you ov10, I was hoping to get your input! Did the Scale Tech ov10 come as a preassembled airframe without motors, and you can either use glow or electric? YES it did I ask because the airframe requirements are different for electrics vs glow. Due to the higher power impulses and vibration from glow engines, it had to be designed for glow, a compromise, and heavier than needed. I should be able to build it much lighter, maybe 6 1/2 lb with retracts!

The kit includes parts(extra balsa!) to build the optional 56" wing, the original uravich build article even recommended it, stating the longer wing doesn't detract from its scale appearance and enhances flyability. I disagree and apparently so did Scale Tech, doesn't yours have the 52" wing? YES it does

I looked up the Rocket 3015-750 (3735-750 ??) motors in your 6 1/2lb bronco. They show it's a 3s motor, max 14.8v, 280watts, and weigh 115g. Did you try flying it on 3s? You're so right and I feel so dumb.......that was the first power attempt on 3S with a GWS 10-6-3 prop and it flew like :Poo: I thought for you to go 4s you'd have to use a smaller prop? So for 4S I repowered with the FMS/RocHobby 3648-770kV and 60A ESC with the MAS 11x7x3 props that I indicated initially. The 3648-830 motors that I have are close to the power upgrade motors offered for P-38, which are 3648-880. So I should be good, right? The 880kV upgrade was for a 2 blade. I think you'll need to measure the current draw and be ready to use a 70A ESC for the 830kV motor Your input is greatly appreciated ov10!

Here's the FMS motor I repowered with:

https://www.motionrc.com/collections/motors/products/rochobby-3648-770kv-motor

You can find the specs sheets on all FMS motors that I published here:

https://www.hobbysquawk.com/forum/electronics-and-rc-accessories/motors-and-power-systems/58518-fms-motors-specifications-pdf-spread-sheet

[Boots Whirlygig]

Thanks ov10. I do have a GT Power 130A meter coming. I ordered it from Amazon as it's currently out of stock at MRC. The picture on Amazon of it shows it has bare wires tho, I thought it would have some sort of connectors or alligator clips? Hopefully I can figure it out!

When I looked up your 3015-750 motors, they are using the motors stator measurement, and also gave the external dimensions as 3735, the standard used by MRC motors.

Too many different ways to size motors. Too many different battery connectors. Too many different propellor shafts and on and on. It really shouldn't be THIS difficult! :Angry:

[OV10]

I hear ya regarding the difficulty but like anything else in this world the manufacturers aren't going to collude to an amicable outcome for us modelers.
Fortunately the trend in the last couple years for motor can sizing has pretty much standardized.
The GT Power Meter is manuf/sold(even by MRC) without connectors. Makes sense because of the variety of connector user choices.

Just keep prodding Alpha along with me until we get a foam one that will be better all the way around than this balsa/ply one that I still highly value. ;)

[Boots Whirlygig]

So are you still flying your OV10, ov10? Do you find it difficult to transport? I live just south of Columbus Ohio, and knew a Charlie Brown here. He was a Crown forklift technician where I work and into classic cars. I haven't seen him in years.

[OV10]

Yes I fly it a half dozen or so times a year. Did a couple sorties with it at the 2016 NEFI event in Muncie. Transport issues aren't really a concern for me if you look at my trailer pics that Gman posted over on the "On the road to NEFI" thread from last year. Believe it or not my name is pretty common and I'm not him.

[Boots Whirlygig]

I will be watching for the NEFI event, do you know when it is as I would love to attend. We lived in Indiana from 89 to 92, my youngest of three sons was born there. Then our middle son attended Ball State, I stopped in Muncie once and toured the museum and bought some r/c plans, its a beautiful facility!

[Boots Whirlygig]

Ok I found the announcement for NEFI 2017! Hopefully I'll have an interesting plane to bring ov10. I'll bring the Opterra for sure, if it survives the next 4 1/2 months. Well, I'll have the FW F-16 V2 4s to bring, I KNOW I'm not touching that!
I

[Grossman56]

Hey, great to hear Boots, look forward to seeing you there!!

Grossman56

[IfIHadWings]

I just got home from the Perry GA swap meet with a Hobby Hanger OV-10 kit found buried in a hobby shop’s inventory. $50 and it looks like everything is there!

I‘ve read this thread and many on RCGs. I’ve seen OV-10’s Bronco fly at Joe Nall/eWeek. A lot of great tips and advice.

OV is number two in the pattern at my bench behind the VQ Dauntless. Hopefully fly the OV later this year.

[OV10]

I just got home from the Perry GA swap meet with a Hobby Hanger OV-10 kit found buried in a hobby shop’s inventory. $50 and it looks like everything is there!

I‘ve read this thread and many on RCGs. I’ve seen OV-10’s Bronco fly at Joe Nall/eWeek. A lot of great tips and advice.

OV is number two in the pattern at my bench behind the VQ Dauntless. Hopefully fly the OV later this year.

NICE SNAG IFHW :Cool:You will love how that flies.
If I had that kit to do over again, go with the FL power system from the Tigercat;)

[IfIHadWings]

NICE SNAG IFHW :Cool:You will love how that flies.
If I had that kit to do over again, go with the FL power system from the Tigercat;)

Funny how things work out....

So I’m at a friend’s house yesterday and mention your suggestion. He has a FL Tigercat but swapped the motors. He reaches into a bin, hands me two FL 600kv motors and the props. Says enjoy and let me see it when it’s finished.

There are are some extraordinary people in this hobby...

[OV10]

A HH :ov10for Fiddy and now free FL props/motors :P......................seriously, that is sweeeeeeeett and I'm:Drooling:with envy ;)

[TBolt]

Hello OV-10 fans, do any of you have the MAN article on the 52" wingspan OV-10 you are willing to share?
I recently picked up a kit, and would like to read up a little on it.
Great tips on this thread, thank you all for the info.

Victor

[Boots Whirlygig]

Hello OV-10 fans, do any of you have the MAN article on the 52" wingspan OV-10 you are willing to share?
I recently picked up a kit, and would like to read up a little on it.
Great tips on this thread, thank you all for the info.

Victor

Sorry Victor, I looked for my copy but that’s a lost cause. I do remember the article dealt with its construction which is very conventional and straight forward and Dated. It’s designed around a pair of .25 engines. The electric conversion deals with brushed motors with gear boxes and a brick of nicads. We’ve come a long way baby!