1/4 scale Cub??

[GeeBeeFan]

I'm looking into building a 1/4 scale Piper Super Cub, I have a really good reference...plans to build a full scale version! I would like to build it as authentic as possible but I'm running into a problem. Are there any flat four engines that look authentic and could carry a perfect scale cub? The only scale looking one I've found so far is the OS engine but I dont think its big enough to do the job. Any ideas? Thanks.

[Mike Smart]

Do you mean the OS engine is not big enough power wise or big enough physically to scale.
As an example an OS Gemini twin cylinder four stroke will easily fly a 1/4 scale Cub.

Mike

[GeeBeeFan]

Okay I dont know what I was smokin earlier! Sorry about that, I guess I just didn't realize the exact size of this cub. Now that I've done a bit of homework, I realize that the OS four cyl. is acctually a bit big! To use the OS engine, accurately; The plane would have to be something like 1/3.85 scale, or maybe it was just a mathematical error on my part. But none the less the OS engine would look decent in the cub. I'm not positive because I can never be sure whos measuring what, where, etc... You know how it goes. So do you think the OS four cylinder has the power to pull a fully detailed 1/4 scale cub? I know its a bit of an opinion question and that I will only truly findout closer to completion.

Thanks.

[Mike Smart]

GeeBeeFan,

I don't think you would have any problem at all, unless you are going to build it out of oak:)
My own plan for a 1/4 scale Cub weighs in at around 12-14lbs and flys realistically on a .91 two stroke or 1.20 four stroke.

Mike

[Haldor]

A friend of mine had a 1/4 Cub (Plain Cub, not the Super) and his flew wonderfully on a OS 1.20 twin old vintage. Power of that one would be equivalent to a new .91 single 4stroke.

[GeeBeeFan]

Okay, now that my little mathematical error has been sorted out, I only have one remaining problem....A 1,200 dollar problem! Now I just have to wait for OS to bring their price down a bit. Thanks guys.

[Tim Jonas]

I have the Sig 1/4 standard Cub with the OS FT160 twin in it. Very dependable engine which looks awesome in the cowl. It is much more engine than the plane requires, but it was well worth the expense.

[Citrorob]

The OS engines are beauties but expensive, how about a 2T petrol engine?

[Tim Jonas]

I've seen Zenoahs in Cubs, but you have to do an awful hack job to get it in the cowl.

[GeeBeeFan]

I know there's always a cheaper route. If I'm going to build this thing just like the real thing is built then I've gotta have an accurate, scale engine. Unfortunately, if I'm not mistaken, the OS 4cyl is the only game in town. So if there's a cheaper 4cylinder in the appropriate size range, PLEASE let me know!

Thanks.

[Tim Jonas]

I believe you are correct. Saito has twins and radials.

[Haldor]

For a 1/4 Super Cub I'd look close on this one : http://horizon.hobbyshopnow.com/products/description.asp?prod=SAIE182TD ($670)

A plain 1/4 Cub would be perfect for this :
http://horizon.hobbyshopnow.com/products/description.asp?prod=SAIE100T ($500)

The bigger 4cyl 3.0 OS motor you're powerwise in the 1/3 scale domain ad its way too big for a 1/4 model of this kind.

[Citrorob]

http://horizon.hobbyshopnow.com/media/images/brands/g-80engine.jpg

This 80cc twin from zenoah should do!

Rob

[pda4you]

Yea an 80cc twin on a 1/4 scale cub. A 7.5 lb motor on a 10 lb airframe. Hmmmmmmmmm

[GeeBeeFan]

I have no problem up scaling my idea just to go that extra step. I know I'll probably never get around to building this thing but whenever I do get around to it I want the four cylinder! Putting a two cylinder engine in a scale cub is just not something that I dont want to do, my kind of scale is a little different than most people. Thanks for the advice.

[Tony H]

GeeBee

I’ve uploaded a picture (I hope) of the 1/4 scale Continental cylinders I’m working on for my 1/4 scale GP Spacewalker. They are made from 24 plies each of aircraft plywood along with vacuum formed valve covers and push rod tubes, intake and exhaust manifolds made from off the shelf plastics. Strictly speaking they are not scale. That’s just not possible using this method. However they are as close to scale as I can make them using this type of construction. And much more realistic than anything I’ve seen. The 1/4 scale will weight slightly less than 6 ozs complete.

I’m also finalizing a set of 1/3 scale (I have a 1/3 Sig Spacewalker and a 1/3 scale Balsa USA Der Jaeger which will look much better with my cylinders.

A friend is almost ready to fly a set in his GP Spacewalker which has a 4 Stroke. This will tell us how they stand up to vibration. If all goes well, I may make them available as kits. There is a lot of laser cutting involved as well as some time gluing the jugs together (they need to be done on a jig), so I don’t think they will be inexpensive. I’ll know more about that after I optimize my laser files to minimize slew time and see what he can do in a production environment.

One other comment – an internal combustion engine with all four cylinders may require some planning to work the exhaust system and needle valve around them.

I’d appreciate it if you (and any others) would let me know what you think regarding kit production.

Tony

[GeeBeeFan]

That's AWESOME! I'll probably use this method on a few of my other projects, it would make it A LOT easier if you had a laser cut kit. I can only imagine trying to hand cut each piece:eek: I'm still not sure what I'm going to do but I still have to build an airframe and you know like finish a few other projects first, so I'll keep you guys posted. Thanks.

[Hangaround]

There is room for a ZDZ 40 inside the cowl on a BalsaUsa 1/4.
Mine has more than 100 flights, an there is no lowspeed/stall penalty compared to the same plane with Laser 1.5 or the Zenoah G23.

There is a vid of it here (http://www.lomcevak.net/modellfly/vids/seilflytrekk.avi) (26 MB) acting as a glider tug. There is no mods to the airframe other than 6mm aluminium tailbracing and thin plywood skin on the vertical stab/rudder.
The glider is a multiplex thingi at 3.7m.


Sam
Norway:cool: