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-   -   Park sized "Fun Cub" ? ( Graupner Stinson Voyager ) (http://www.Wattflyer.com/forums/showthread.php?t=72844)

Brian VT 12-22-2013 11:17 PM

Park sized "Fun Cub" ? ( Graupner Stinson Voyager )
 
I have a Park250 2200kv 55W outrunner and rest of electrics that I'm not using.
I'd like to have something like a Multiplex Fun Cub, but smaller. I'd set it up as a bush plane.
Tough and inexpensive would be ideal.
Help with finding an airframe ?
I thought I had a candidate in the HK J3 for $35 but the reviews don't look good (tail heavy).
http://www.hobbyking.com/hobbyking/s...dproduct=16341

fhhuber 12-23-2013 01:36 AM

Tail heavy is usually the fault of the person setting up a plane that came as an ARF or kit.

It might require a little effort with some to be able to move equipment to get the CG correct but its certainly possible on a foamie ARF such as the one from Hobby King.
Its just hard to go wrong with a foamie cub as long as CG is correct, weight is reasonable and you have sufficient power.

Even the Harbor Freight Cub will fly fine if you just put a decent RX in it. The TX and RX that come with it are trash.

I can easily believe HK to have recommended an inadequate motor... I never believe their recommendations for equipment.

Brian VT 12-23-2013 01:45 AM

Well I haven't found any other options.
Do you think it might be worth putting my gear in that plane ?

fhhuber 12-23-2013 02:32 AM

Not familiar enough with that plane or your motor to know if they are a good match.

The wrong motor will make any aircraft unpleasant to fly... or potentially even unflyable.

Brian VT 01-03-2014 01:39 PM

Graupner Stinson Voyager
 
Well I stumbled onto a Graupner Stinson Voyager at Graves RC.
It might have been the last one out there ? Got it yesterday.

http://www.gravesrc.com/ProductDetai...R6252&CartID=1

https://shop.graupner.de/webuerp/ser...11&language=en

I'm a bit of a newb, and more of a BNF/PNP guy, so this will be a challenge. http://static.rcgroups.com/forums/im...es/redface.gif
Not sure which glue is best for this foam. I think I should add main wing struts ?
I hope to put tundra tires on it and would also like to get/make floats for it (mainly for snow). Maybe even cut in some flaps ?
The motor bay is designed for a Speed 300 can, so I guess I'll have to rig a motor mount for my Park250 BL outrunner and try to keep the CG where it needs to be.
Any tips/advice appreciated ! http://static.rcgroups.com/forums/im...lies/smile.gif

solentlife 01-03-2014 03:41 PM

Tips ?

Keep it simple and I'd leave of the floats and flaps until you are sure it flies and has the power to cope with extras.

Nigel

Brian VT 01-03-2014 04:02 PM

Makes sense. Getting ahead of myself/too excited. :oops:
Thanks.

JDMJim 01-07-2014 05:31 AM

Buy a MPX Funman

Brian VT 01-07-2014 12:27 PM

Quote:

Originally Posted by JDMJim (Post 936457)
Buy a MPX Funman

The FunMan and FunCub are just what I'm looking for except that a 30" wing span is much more portable so here I am with the Graupner Stinson.
Hopefully I can keep it healthy for a while as it's discontinued and I haven't seen much for parts available. I haven't started the build yet.

Brian VT 01-10-2014 02:35 PM

Still debating on the motor for this.
The cowl is hollowed out/formed for a 24.4mm diam. brushed can Speed 300 to be glued in. I believe the side/down thrust is molded/built in.
I think I’d like to use the brushless Park250 2200kv “bell” motor (22mm diam bell) I have.
I’m thinking I would rig a 24.4mm +/- “tube mount” for the bell motor that I’d glue in the mold for the Speed 300 can and that would automatically give me the side and down thrust as designed into it. Make sense ?
It seems like it would work but I’m also wondering if the Park250 2200kv is enough motor. Should I have a lower kv ? Just looking for scale/sport power.
I could enlarge the cowl opening for a larger bell motor, if needed.
WWYD ?

thepiper92 01-10-2014 06:01 PM

Quote:

Originally Posted by Brian VT (Post 936706)
Still debating on the motor for this.
The cowl is hollowed out/formed for a 24.4mm diam. brushed can Speed 300 to be glued in. I believe the side/down thrust is molded/built in.
I think I’d like to use the brushless Park250 2200kv “bell” motor (22mm diam bell) I have.
I’m thinking I would rig a 24.4mm +/- “tube mount” for the bell motor that I’d glue in the mold for the Speed 300 can and that would automatically give me the side and down thrust as designed into it. Make sense ?
It seems like it would work but I’m also wondering if the Park250 2200kv is enough motor. Should I have a lower kv ? Just looking for scale/sport power.
I could enlarge the cowl opening for a larger bell motor, if needed.
WWYD ?

The weight of the plane is stating 30oz...seems to be a misprint. If it is 12oz with a 7 cell, it would be around 10, maybe less, with a 2 cell. I would say a Park 300 would be better, it's always better to have more power than needed, rather than never enough power, at least that is what I feel. You would have to go through more trouble mounting, but I would personally go through the trouble of doing that. As you already have the 250, maybe going to the smaller Hobbyking Mini J3 would be a better choice, as well as cheaper. As Nigel stated, you have to keep it simple, for the 250 could be borderline power for the larger plane.

Basing it off the Tuff Trainer I once had, the weight and size is similar (other than the exaggerated wingspan). The Tuff Trainer was using a 2822 motor, or something along those lines, with 3s power. That gave it ample power for anything. While you would be getting more RPM out of the Park 250, it will prefer a smaller prop, probably 6-7 inches, and if the weight is not kept down, heat will build up fast on the Graupner. With the Hobbyking, it is smaller plane, and thus will not push the motor as much, and I feel it would be much more suited to a 6 inch prop. Even looking at the motor that is with the cub, it is roughly the same as the 250, though less kV.

Brian VT 01-13-2014 02:53 PM

Good stuff. Thanks.
Yeah, Graves' site is a misprint. Graupner site says 330g.

Well I think I'm gonna use the guts from my Edge 540QQ that I've been scared to fly due to my lack of skills and maybe sell that airframe or store it for when I'm more confident.
It's a Park 280/1800kv on 3S. It has a 6.8x3 prop. on it but I'll probably start out with a 6x4 since the motor shaft is only @ 4 1/2" from the ground (even after I added bush wheels). Or maybe try a 5" or 6" 3-blade.

Brian VT 01-17-2014 03:27 AM

I took the Park 280 from the 540QQ. I glued the motor's X mount to the the face of a tube (plastic electrical conduit). The tube is a bit smaller than the channel for the stock motor. I'll wrap the tube with double-sided tape and the fit is then perfect. The 22mm motor has good side clearance too. The other motors I had considered would have required enlarging the cowl opening.

http://i388.photobucket.com/albums/o...ps21c23eda.jpg

http://i388.photobucket.com/albums/o...ps7174bc6f.jpg

http://i388.photobucket.com/albums/o...ps0e4ee76d.jpg

http://i388.photobucket.com/albums/o...ps1f4a3ff4.jpg

Brian VT 01-22-2014 03:04 AM

I'm getting there. :o Looking for some opinions on motor location.
I like the look of having the front of the motor flush to the front of the cowl but then it looks to me like the prop. is too far away from the cowl.
If I slide the motor back to have the prop. closer to the cowl then I have a hole/gap back to the motor.
Which do you think looks better ?

Fore:

http://i388.photobucket.com/albums/o...psbb34aa35.jpg
http://i388.photobucket.com/albums/o...pscfe38dae.jpg

Aft:

http://i388.photobucket.com/albums/o...psa5d9ad46.jpg
http://i388.photobucket.com/albums/o...ps3c734d90.jpg

Turner 01-22-2014 03:30 AM

Can you reduce the distance between the motor and prop? Maybe shorten the shaft or use a different prop adapter?

thepiper92 01-22-2014 03:32 AM

The motor further back looks better to me, although you should maybe think of cg, further forward will help tail heaviness without more weight.

Brian VT 01-22-2014 12:56 PM

Thanks for the replies.
I don't see any way to shorten the shaft, unfortunately.
CG is certainly the main concern but I wanted to ask opinions on appearance 1st.
The only spec. I have for cg is to not fly with it more than 50mm and it's pretty close to that now with a 3S/800mah lipo. Maybe I can get away with moving the motor aft if I add a prop spinner or maybe I can get away with a 3S/500mah or even go to 2S ?
Many unknown variables will make for a nervous maiden flight. :oops:
Any more advice is always appreciated.

Turner 01-22-2014 02:16 PM

You really won't notice the prop to cowl distance once in the air. I would mount it forward, especially if that helps get the CG right.

thepiper92 01-22-2014 03:43 PM

Quote:

Originally Posted by Turner (Post 937822)
You really won't notice the prop to cowl distance once in the air. I would mount it forward, especially if that helps get the CG right.

I agree. While it looks better on the ground with the prop further, it is better to have it further forward and possibly have it a tad nose heavy, which will be easier to fly. It you want to perfect balance, with no nose heaviness, you can easily move the battery back, or add a tiny weight on the tail.

Brian VT 01-24-2014 02:16 PM

Well it looks done and I thought I'd be done tonight.
I made up some wing struts with wire through coffee stirrers.
I wasn't happy having to take the wing off to stuff the lipo into the fuse amongst all the other guts and not being able to use it to adjust the cg so I rigged a "cargo box" under the belly to hide the lipo there. It was a plastic package that pop rivets came in. I think it fits okay with the "bush plane" look.
I thought I was done until I realized that I should have cut free and hinged the control surfaces. They are already failing. :mad: I guess that's my next project before the maiden flight.

http://i388.photobucket.com/albums/o...psb00e07bf.jpg

http://i388.photobucket.com/albums/o...psf3109c1d.jpg

http://i388.photobucket.com/albums/o...psc1be0ff3.jpg

thepiper92 01-24-2014 03:39 PM

Quote:

Originally Posted by Brian VT (Post 937977)
Well it looks done and I thought I'd be done tonight.
I made up some wing struts with wire through coffee stirrers.
I wasn't happy having to take the wing off to stuff the lipo into the fuse amongst all the other guts and not being able to use it to adjust the cg so I rigged a "cargo box" under the belly to hide the lipo there. It was a plastic package that pop rivets came in. I think it fits okay with the "bush plane" look.
I thought I was done until I realized that I should have cut free and hinged the control surfaces. They are already failing. :mad: I guess that's my next project before the maiden flight.

http://i388.photobucket.com/albums/o...psb00e07bf.jpg

http://i388.photobucket.com/albums/o...psf3109c1d.jpg

http://i388.photobucket.com/albums/o...psc1be0ff3.jpg

Looks good, I was thinking maybe painting black windows would improve realism. Of course it doesn't matter when flying, but when sitting there, it would look better. Also, maybe "rubber" tires and rims.

Brian VT 01-24-2014 07:10 PM

Thanks. I agree that the blue windshield looks odd. Those are stickers that came with it. I'm scared to try black marker on it in case it doesn't "take" and ends up looking worse.

Seems confusing that you quoted my last post and we have to scroll through the pics twice to get down to here.

Brian VT 01-27-2014 03:20 PM

I used Blenderm tape on the ailerons and elevator. I used 2 micro pin hinges on the rudder because there's very little space at the bottom to attach tape.
Ready for maiden and, of course, the wind has been 15mph+ since.

Brian VT 02-01-2014 07:30 PM

She flies. :)
I had a friend maiden her today. It did well but needed just a bit of weight in the nose. I'm gonna move the battery/cargo box forward a bit. The wheels rolled fine on a snowy dirt road. 2 perfect takeoffs and landings. I think this is just the plane I was hoping for. A little dihedral is probably the only thing that it would need to be perfect for my present skill level (about a dozen flights with 4ch.).
I hope to have the cargo box moved in time to fly it before dark today.
So...it's got the electrics from an Edge 540QQ, an APC 6x4 E prop., and Nano-Tech 3S/950mah/25-50C lipo.

thepiper92 02-02-2014 05:11 AM

Quote:

Originally Posted by Brian VT (Post 938812)
She flies. :)
I had a friend maiden her today. It did well but needed just a bit of weight in the nose. I'm gonna move the battery/cargo box forward a bit. The wheels rolled fine on a snowy dirt road. 2 perfect takeoffs and landings. I think this is just the plane I was hoping for. A little dihedral is probably the only thing that it would need to be perfect for my present skill level (about a dozen flights with 4ch.).
I hope to have the cargo box moved in time to fly it before dark today.
So...it's got the electrics from an Edge 540QQ, an APC 6x4 E prop., and Nano-Tech 3S/950mah/25-50C lipo.

I personally found dihedral annoying, at least on a high wing. I dislike the self correcting. If you flown it fine without crashing, then I see no reason why you'd want dihedral really. Also with dihedral, ailerons don't seem as effective, for the battle against the planes tendency to level. Thats how I feel at least.


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