fullmoon_sg

Hi all,

Currently, I'm scratch building a RFB Fantrainer using a "Xerox-ed" plan from a 2001 magazine. The wing span is about 70 inches and designed for 60 size engine. However, I have planned to fly it with OS 55 AX with 10 x 7 blades prop. I know that it would not be a speed demon, but will a OS 75AX or Rossi 65 with 10 x 7 " 3-blades prop makes a difference ?

combatpigg

My Feedback: (3)

The CG is the biggest issue with rear mounted engines. You want an engine that weighs the same as the original, or even less if the original plane needed lead in the nose. Next priority is RPM potential. The "fan" is a cut down prop, so the engine must be able to rev it good to make enough thrust. I'll bet a Jett .60 would do the job... Actually, any engine that compares favorably to the original would be OK. Once you fly the plane successfully with the recommended prop, then you could try more pitch, or a 3rd blade.
These planes have a unique sound and look very cool flying.

dhal22

cool, i'd like to see this one happen.

fullmoon_sg

Hi Combat, the original set-up is ASP 75 with 10 x 7 prop. In fact, the duct fan only allowed max 10" prop. Therefore, I think the current technology, which is OS 55 AX, is comparable to ASP 75 in 2001. Nevertheless, I will upgrade the engine to OS 75 AX if needed. As for the engine weight at the rear, it is about 15 cm behin C.G. Not so bad I think.


Hi David, I will make it happen. Will post video when I have done it. Cheers.

fullmoon_sg

Some update to my building. However, I really need some opinion here. I just did a rough calculation and estimated that the flying weight is about 6 t o7 lbs or between 3 to 3.5 kg. Will my OS 55 AX with 10 x 7 " 3 blades pusher prop is able to fly this plane? I'm not looking at high speed but at least not flying at full throttle just to maintain flyable air speed. Many thanks.

lfinney

My Feedback: (44)

with that much wing area yes it will, but a 60 or 75 would be nice, a 10x8 three blade would be better, the 55 is a torquer, keep on building!

fullmoon_sg

Thanks Ifinney. Right now is to keep the flying weight low. To make flying less stress, I will include a split-flap. Neverthless, if need to, I guess I have to buy a OS 75 AX to fly this machine. Cheers.

fullmoon_sg

Update to my building..

combatpigg

My Feedback: (3)

Your plane is looking real nice! It looks like most of the hard work is finished. How did you finished the fan duct? Is that Monokote or paint?

fullmoon_sg

Hi Combat, thanks for the comment.

The fan duct finishing is not good and I think it can be better. The fan duct is done with 1/16 ply and 2 x 1/16 balsa, and covered with Monokote. Actually, I'm worried of how to build this fan duct as I have no experience with it. However, I managed to find a plastic pipe about 10.5" diameter and used it as a my mould. Here the pictures :.

combatpigg

My Feedback: (3)

It looks like a pretty tough job to make something perfectly round out of wood. Your work looks good from here.
If the wood is soaked in full strength ammonia, it can make the wood real easy to mold. Faster acting than using hot water.
You know, 2 tubes could be used for a mold...[I'm just thinking as I type this].....a solid pipe for the inner mold and a split pipe for the outer mold. A friend built the smaller version of this plane for a Cox TD .049 engine and it was very fun to watch. It was a very smooth flyer that everyone wanted to get a good look at.

cncswiss1

the mold as shown is an external mold, you could inflate a balloon inside everything to "clamp" it

fullmoon_sg

Appreciate both of your tips. I think it will be a great help, probably my next project, building the RC veritgo (the vertical take-off plane). I got this plan from the ebay and it requires some works on the fan duct.

I just can't wait to finish this project and see this plane flying in the air. With the look and sounds of pusher engine, I think I will be enjoying this plane for many many months.

iron eagel

Real nice job on the flap setup.

fullmoon_sg

Thanks Iron Eagel.


Pre-maiden day. Hopeful to have my first 2010 flight by maidening this lovely plane of mine. Everthing is good to go except the canopy.

fullmoon_sg

No matter how hard I've tried, there is no way I can start or flick the engine with the starter. There is no space for my start to engage the propeller soomthly. So, I came out with a easy way to start my engine. This rope can continue to provide two constant turn. Should be good enough to start the engine.

fullmoon_sg

The D-day. Everthing is completed except half-canopy. The best way is to tape the other uncovered canopy....

fullmoon_sg

This is it !!![8D]

http://www.youtube.com/watch?v=c-SvDw0xKU8

combatpigg

My Feedback: (3)

That's amazing!

Congratulations on a great job. That looks like a tough area to fly from but the plane tracks very well.

tIANci

Fullmoon ... nice one! Wanna go EP or not? No need to flick start ... hehehehee ...

iron eagel

Great job!

fullmoon_sg

Thanks Combat. I had modified the landing gear slightly to suit the runway condition. The nose gear was intentional lowered to have more grips and tracking during take-off. Also I have increased the incident of the wings by positive 2 to 3 degrees.

Hahah TianCi, no thanks. Electric is not my cup of tea and I think it is more expensive to operate. I was told the plane would need at least 10s lipo to run it. Anything I think I'm also addicated to nitro smell.

Thanks Iron Eagel.

Pecanpatch

My Brother has the 69" wing span RFB 600 kit and it uses a O.S, .46 with a Tornado 10 x 6 three bladed prop cut down a little bit......... flies great!

garard

You might find this latest jet powered 1/4 scale model of interest. Looks really great. Cheers Gary

https://www.youtube.com/watch?v=NuL9aQksF0s
https://www.youtube.com/watch?v=uzCTrPp19sg
https://www.youtube.com/watch?v=EneATcOnW60

airraptor

My Feedback: (66)

if going to buy the 75 AX might as well buy the 95 AX as it is the same weight if not a tad less. Jett also make a Pusher version of his mufflers that works well. APC make a 10x7 pusher that would be perfect for this application with the 55AX and the Jett pusher muffler.