fokker38cc

Hello
I am finished 2 weeks ago a Slow motion plane , scimitar series from Bill Evans, from a plan of Model Aviation.
The plane make me a star in the flying field and like to make the same plane scaled down to .25 engine, plain bearing
The plane have 61¨of wingspan and have a medium chord of 11¨ to make aprox 660 sq. inches of surface and have a weight of 60 oz. dry ( by careful construction process), and fly very well with a Tower 40.
What ratio to apply to shrink my plan
Many thanks for your time
Jose
Argentina

suthep

Suppose you are satisfied with a wing area of 400 sq.in, the reduction ratio is square root of 400/660. That is 0.77849894416152297091617566531151 on my calculator.

Could I have a look at your plan?

canadagoose

My Feedback: (2)

Try scaling it 3/4 of original size, doing it at this will also scale the wood size down to standard sizes. For example 1/8" balsa would then become 3/32".

BMatthews

For flying wings you need a little more wing area than for normal models because the "stabilizer" is part of the wing being the reflexed part of the trailing edge.

For a 25 sized Scimitar I would not want to go much less then 500 sq inches. That would mean that about 400 of those would be lifing and the other 100 would be for stabilization.

So 500/660= 76%. But this is the reduction in wing AREA. For a linear scale you need to do the square root of 76% so the 25 size model would be 87%. So the 25 sized model will not be much smaller but it WILL need to be lighter. DO try to keep the weight down to 50 oz or less. 40 to 42 would be ideal and would give you almost true out of sight vertical performance.

fokker38cc

Hello
Sirs, many thanks for your time.

BMathews:
Good advise, I will take note of it, for the 40 or 42 engine I need more sharp fingers, but I make this plane to improve my fingers.
I like to make a 25 plane for me and for a friend who have a 25 and like a cheap plane and no problems with hard landings.
I and my friend need to improve fingers we are a lot of distance of vertical performance, but may be a day .........

canadagoose:
yes , we are talking with friends about it, but the fuse dimensions its the same, the width because we have only standard servos

suthep: we are aproaching to these numbers, I am sorry but I have no soft and hardware to
make you a photo of the plane, you can see the photo and description of scimitar series in
RC Modeler site , go to alphabetical index of plan , take the number of Scimitar planes also "polar star" plane and put in the pictorial and the site return a photo of plane and a brief description. Also you can find photos in RC Universe , put in SEARCH window the word Scimitar and the site have photos.
NOTE: all they can say about the Scimitar series planes of Bill Evans is TRUE, nice stall, with small throws is a trainer and big throws an acrobatic plane
I will buy a Scimitar Weed Wacker plan and magazine (flying models) to make a big Scimitar with a Homelite 38 chainsaw engine.Featured in September 2002