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Biggest .049 powered plane?

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Biggest .049 powered plane?

Post  Tinker Terry on Sun Oct 26, 2014 4:01 am

What's the biggest plane an .049 Medallion will be to handle? I am thinking of building an RC plane for my old engine and am considering something around 30inch wingspan. I have a 4 oz plastic fuel tank which should give me over 1/2hr run time. How much would that much fuel weigh? I also have a spektrum ar6210 receiver. Its a six channel so I'd like to have flaps and retracts as well as throttle, rudder ailerons and elevator.

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Re: Biggest .049 powered plane?

Post  roddie on Sun Oct 26, 2014 12:28 pm

That's a difficult question to answer.. "How big" also depends greatly on the type of performance you're looking for. A retract system limits your choices to mostly low-wing. I think that a throttled high-wing design would provide more enjoyment both in; ease of construction.. and relaxing to fly. Have you considered a powered-glider? Construction is more difficult.. but you could build a fairly large model. The "Bird of Time" (B.O.T.) is an example that comes to mind. You could utilize channels 5 and 6 if you add spoilers/airbrakes.

A 4oz. capacity tank is pretty big.. so the closer it's located to the CG.. the better, in my opinion. What do you plan on using for an engine throttle? (just curious)

just my Two Cents here. Reviewing options is always good.. and can help a lot with choosing a design.

EDIT: see "Kim's" recent post for an example of how BIG you could build for the Medallion!

https://www.coxengineforum.com/t7361-3-meter-bot-flying-on-a-beautiful-fall-eveing-over-in-my-hometown#92646
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Re: Biggest .049 powered plane?

Post  Tinker Terry on Tue Oct 28, 2014 1:20 pm

I plan to out the tank centered on the cg so as to avoid balance changing as fuel is used up. My 049 medallion has the OEM exhaust throttle barrel, but when $$$ permits I would like to get a carb, same as the TD. Might even get a TD cyl and piston so I can run an exhaust pipe.
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Re: Biggest .049 powered plane?

Post  Cribbs74 on Tue Oct 28, 2014 4:56 pm

Terry,

Fuel weight depends on what fuel you plan on using. The oil content plays into it, 1 oz of fuel will weigh close to 1oz perhaps a bit less, but not all that much.

I would try to keep AUW around 20 oz or less. Maybe RC guys can chime in and help here.

If you plan in running a pipe, be aware that a TD cylinder has SPI and performance could be hindered.

Ron
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Re: Biggest .049 powered plane?

Post  JPvelo on Tue Oct 28, 2014 5:52 pm

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Re: Biggest .049 powered plane?

Post  Surfer_kris on Tue Oct 28, 2014 6:20 pm

Around 30" is fine, but it also depends on what type of plane you are thinking of. For a glider type it can be a lot larger while a sports plane is better around 26-28". With a modern radio these will come in around 10-12oz in total weight without any problems, while even up to 20oz will fly fine at full throttle too.

A 1oz tank is usually more than enough for a 10 minute flight, it is better to land and refuel, than to fly for very long times anyway.
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Re: Biggest .049 powered plane?

Post  Cribbs74 on Tue Oct 28, 2014 6:28 pm

Listen to Kris, he knows his stuff!

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Re: Biggest .049 powered plane?

Post  ian1954 on Wed Oct 29, 2014 6:27 am

I would have agreed with Kris but for the SIG Hummer.

Wing Span: 34 in. (864 mm)
Wing Area: 212.5 sq. in. (13.9 dm²)
Length: 30-3/4 in. (781 mm)
Flying Weight: 20 - 26 oz. (567 - 737 g)
Radio Required: 2-Channel
Wing Loading: 13.5-17.6 oz/sq.ft.
Engines: .049-.061 (0.8 - 1.0 cm³) 2-Stroke

Although mine is electrified - I found it too fast for me. I thought that having the advantage of an electric motor with full throttle control would let me slow it. Alas - not so. It doesn't want to glide and will stall (badly). However, it is fast and agile (unlike me!) but needs a bigger space than I have to fly in.
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Re: Biggest .049 powered plane?

Post  Surfer_kris on Wed Oct 29, 2014 7:37 am

If you want to fly slow you need to reduce the total weight, it is as simple as that. To me the weight is more important than the wing-profile, and with modern radios and servos there is no reason to build them heavy...

A good way to analyze a plane is too look at the cubic wing loading, there is a simple calculator here for instance; Cubic wing loading

The cubic wing load is independent of the scale and will tell you about the flight characteristics of a plane. If you dial in the numbers of the SIG Hummer you see that it is a scale plane type, bordering on a racer. So yes it will be very fast and agile but you also need to match it with a strong engine. I'm guessing a Norvel .074 would be better suited, even if a strong TD should fly it too.

So back on topic, one cannot simply give a certain wingspan and from there tell if a throttled medallion engine is well suited...
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Re: Biggest .049 powered plane?

Post  ian1954 on Wed Oct 29, 2014 8:07 am

Agreed.

This boy flies at walking pace



but it is not 1/2A. More like a .40.

Wingspan is 52" but it weighs 58 1/2 oz.  

As Kris says "one cannot simply give a certain wingspan and from there tell if a throttled medallion engine is well suited..."

Below is a KK Radian CL model (22") wingspan with my Sig Hummer. Both intended for the same size engine. The Radian has the 049 Medallion installed

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Re: Biggest .049 powered plane?

Post  1/2A Nut on Wed Oct 29, 2014 10:03 am

Fun fly / slow fly / indoor all take / require big props for thrust, it boils down to what's practical for a methanol running .049.
If you can source a thin bladed 1/2A sized hubbed 6.5 x 2 perhaps a 7 x 2 this is your limitation to drag the airframe around outdoors in calm winds or sub 7 mph. I have fabricated gear box for the 1/2A engine the ratio was 2.5 to 1 for a 8 x 4 Wink
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Re: Biggest .049 powered plane?

Post  duke.johnson on Wed Oct 29, 2014 10:35 am

I had a Gentle Lady 2 meter glider that I put up with a baby bee on a 5cc tank. It was great, I'm going to build another one. Of course it is a big floaty wing, 2 channel, and belly lander.
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Re: Biggest .049 powered plane?

Post  Tinker Terry on Wed Oct 29, 2014 1:24 pm

Thanks for the input everybody. I used I think a 6x5 wooden prop on this engine years ago and got enough speed on my baby ringmaster to demolish the plane due to dizziness caused by too short lines.
I am pretty much decided on a wing around 28-30inches with the cord adjusted to give me 15-18oz/sq.ft. wing loading. Flaps should give me reasonably slow landing speed and flapeons for maneuverability. A moveable tailplane and a big rudder that can be pared down to smaller size.
Have long been thinking about a gear box and would like to see some info on how to build one.
Some info on diy/home made main gear retracts would also be nice.
I have seen listings for cox Texaco props 7&8 D. Is there some major difference in the Texaco engine that makes these big props feasible?
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