hi guys,
just recieved my plan from germany , great service and very quick , i will post pics and the build as i go , to start with it will be the canopy plug and the cowl plug build. back to the dust room.

regards
steve.

canopy plug well under way filler applied forfinal shape and sand.

Hi,

Nice - will be interesting to follow this. I also got the Supra Fly 2500 drawing from FMT last week but I will not build it now. In the 4 page building description (in German) it is mentioned that on Supra Fly 2500 it was used a EZ Supra Fly 60 canopy - maybe it is possible to find such canopy? It is also mentiond the engine cowl and wheelpants that was used came from a EZ Diabolo 904 (120?). Maybe Singahobby could have some cowl and canopy left?

/Bo

hi bo,
i have a friend who can pull the canopys for me and i can make the cowl , so this is not a issue , the cowl will be glass the plug is well under way as i type, i can always produce these for others if they wish for a minimal cost.

regards
steve

cowl plug well underway , just fill and shape.

Original and unusual build thread!

Looking forward to this. I see those plans are from and EZ/OK kit.
[ul][*] Full aircraft specs would be nice to have - would you mind posting them?[*]I assume the 2500 refers to the engine displacement - 25cc (1.53 cu in)?[*]What will the model be powered with?
[/ul]
Further information on it's baby brother - the SF 25 (also by OK Model) - will be added to the 20 size conservation thread in the near future. And while we're talking about Hanno's designs - so will info on his Mystic!

David.

hi,
plans are from a company in germany , the aircraft will have a YS 160 or 170 , not sure on what one yet , wing span is 2 meter .
will be very light so will have lots of power.

rgds
steve

Steve,

nice. What is the fuse length and wing area? Stab span? Do the plans indicate a target weight? I assume you'll be building to ~9-10 lbs if very light?

David.

Hi,
I can fill in with some specifications since I have the drawing in scale 1:1 and construction article from FMT (Flugmodell und Technik):

Supra Fly 2500
Designed by Hanno Prettner

Wingspan: 2058 millimeter (81.02 inch)
Stab span: 770 millimeter (30.31 inch), measured by me on the drawing
Fuselage length: 1710 millimeter (67.32 inch)
Flying weight: 5500-6500 gram (12.13-14.33lbs)
Engine: 20-30 cc (2- or 4-stroke)
EWD: +0,5 degree
Engine down angle: 1 degree
Engine right angle: 1,5 degree

According to the 4 page construction article Supra Fly 2500 is basically about 20% enlarged EZ-Supra Fly 60.
Hanno Prettner flew his Supra Fly 2500 with a Super Tigre S 3000 (30 cc) two stroke with pipe and 18 x 10 prop at about8000 RPM.
No mention in construction article what the wing area is. No target weight mentioned other then the span between 5500 - 6500 gram (12.13 - 14.33 lbs) but Hanno mention it should be no problem to get a weight under 6000 gram(13.23 lbs)so I guess the target weight is between 5500 (12.13 lbs) to 6000 gram (13.23 lbs)to aim at. Hanno warns for heavy engines (I suppose he is thinking of gasoline engines that tend to be heavier).
To bad the FMT construction article is in greyscale only so the photos of Hanno Prettners Supra Fly 2500 is not so good - anyone have color photos of his Supra Fly 2500?

/Bo

Bo,

thanks for the details - very informative.

This is a bigger bird than I thought. I guess 78-82" makes sense for a 1.8 cu in engine model.

There have been some photos in color of the SF but mostly they are from EZ's ARF's - I'm not sure if that scheme was the same used by Hanno's original.

David.

Hi Steve,

I am happy to see that there are more people interested in this plane. I have the plans too, and was looking at modifying the construction to make it lighter. The construction "as is" is just a scaled-up old style pattern plane construction, which makes it heavier than it needs to be. The weight that is indicated on the plan - 5500 to 6500 grams - discourages me a bit to put an MVVS 1.6 or a Super Tigre 2300 in it, even though it would be piped. The modern style pattern planes weigh up to 5000 grams with more than that kind of horsepower, and I expect the Supra Fly to need more because of the higher flying speed.

I am eagerly watching the construction thread, and I am curious what will be the final weight ready to fly!

Keep up the good work,

Kris

Bo,

As I'm thinking of building an 81" span/934 sq in model (different model) to 9.5 lbs (4.3 kg) it would be helpful to know the wing area of the SF 2500. It might give me an idea of my chance at succeeding.

From the plan, measure the root and tip chords and multiply them by 40.5" (half the wing span). This is not 100% accurate but close enough. The mean aerodynamic chord (MAC) will actually give you a better measurement of area but the previous will be good enough.

On the other hand, if the plan is digitized, a copy would be much appreciated.

Thanks, David.

These are the dimensions i measure on my plans :

root 428 mm,
tip 258 mm ( where the wing joins the tip block)

Best regards,

Kris

Hi,

I loaded the drawing of Supra Fly 2500 (after scanned) in a drawing program and resized it so it had correct measurment (I measured half the wing that has a span of 1029 millimeter).
Then made polygons over wing area and stab area and the area was this: see images below.
I hope I converted from square mm tosquare ft and square meter correctly (I used an online converter I found on internet).

/Bo

Gents,

thanks for the info and calculations (if they were done as a result of my prodding!).

Based on Kris' measurements, a crude MAC is 13.51". Here's how:

Root chord, R = 428 mm = 16.85"
Tip chord, T = 258 mm = 10.16"
Mean double chord, C = R+T = 27.01"
MAC = 0.5C = 13.51"

At an effective span of 78.5" (removing a total of 2.5" for the wing tips) we have a half span (panel, P) of 39.25". Now watch this if you haven't seen it before:

Wing area = C*P = 27.01*39.25 = 1060 sq in.

Bo, what was your polygon measurement? Right - 1061 sq in...

David.

By the way, in Firefox's Google search box (top right), ever tried to type in things like:

7.369 sq ft in sq in

7.369 sq ft in dm^2

Do it, you'll be surprised. Just about every other conversion works as well. I use it all the time.

David.

David,

What You calculated was exact same as polygon area for wing area measured on the drawing by me!!
Amazing accurate calculation!

My measured wing area was 7.36928 ft².

7.36928 ft² = 1061.176 in² (when using an online converter)

/Bo

hi guys ,
the cowl plug in the making , i will post the pics to show how the cowl begins it`s life. stage one: profile front rear sides and width . stage two `BLUE FOAM inserted into the spaces . stage three : sand to shape . stage four : fill the cowl ready for a sand of when dry. The plug is now drying so i will post the next pics when the cowl is sanded ready for glassing.

Your cowl plug is looking good. What iceing recipe did you use. Epoxy and microballons. Should sand easy.
Joe

Cool!

What do you use for the fill? And what, if anything, is needed over the fill prior to glassing to allow the mold to be pulled? Actually, with that shape I can't see how the mold can be pulled so I imagine the cowl is made in two sections (left and right) and later joined?

David.

hi guys,
just standard house hold filler (poly filler )... sands very easy into the foam , two piece mould i will show the splitter board etc. later on . just keep running out of time!!, must give this work lark up!!.

regrads
steve

ok,
slow but sure we are getting there, plug will be sent of this week so the canopys can be vac`ed out. canopy plug is solid balsa then glassed , 2 to three coats of resin cut back then 2 k clear. thn cut back and polish.

cowl plug sprayed and ready for waxing. 2k paint used .

hi,
plug now has the splitter board around the plug , this devides the the mould in to 2, the splittter board is perspex.

9 coats of wax applied 1 hour wait between laters , long day.The wax is called KANSTIK WAX SILICONE FREE. from the usa.

one half complete .

polish and clean now.