Stuntpiloot

Hello,

For my next project I want to build a V-max, it has the following specs:
wingspan: 1000mm
Lenght: 1030mm
Area: 18,4dm2
Weight: 1300gr.
Profile: Ritz 1-30-10

It is original designed for a 3.5cc engine, and has been proved to fly >350km/h

What I want to do is put a 6.5cc (.40 for you Americans ) MVVS engine on it with rear exaust (RPM apx. 20.000 - 23.000)
Because of the bigger engine I want to enlarge the plane with 10 or 20 %
With the 20% increase the wing will have the following specs:
Wingroot thickness: 3.00cm
Wingroot Lenght: 30.2cm
Wingtip thinckness: 1.6cm
Wingtip Lenght: 16cm
Wingspan: 1200cm

Now my question to you guys is: Is this an reasonable thing to do, or would the thicker profile mean more speedloss that what the increase of the engine would give?
What wingsises/thickness do you use on the speed models.

PS: I'll see if I can scan an image of the plane and I'll post it
here.

im_a_rcav8r

That sounds good to me. If you want to double your speed, it takes 4 times the power. So using that logic, if you double your engine power, you should be able to add 20% to the size with no problems at all. I would not change the thickness of the wing, but thats just me.


by the way, did you want to type 120 cm as the length of the wing? 1200 cm is awful long for a .40 or 6 cc engine! Or perhaps 1200 mm?

Stuntpiloot

Oeps, 1200mm that is..... :spinnyeye

1200 cm hmm, we could be soaring with that kind a wing

Stuntpiloot

Here's one pic I scanned .......
I'll try to post a color picture later.

Stuntpiloot

Pic added

Stuntpiloot

And another one...

You guys have any idea how fat this one will go?
20% enlarged with an .40 engine with rear exhaust that is.

(The one in the picture does 337km/h with an .20 engine)

Paulus

Now that should go seriously fast with an MVVS FAI GRRT engine. Or even better: MB 40

The wing thickness(3 cm) looks a bit thick though. The F3D airfoils have a minimum thickness of 22 mm for example.

Paul

Razor-RCU

My Feedback: (50)

What on earth is an MB-40?

I just traded a MVVS GRRT RE which would be a nice fit!

What is it 1 MPH is .6 K?

Stuntpiloot

I thought 1 mile is apx. 1.6km, this results in 1km = 0.63mile

Paulus

Here's a pic of the MB 40. Currently the most populair F3D engine.


Paul

Stuntpiloot

This is the engine I plan to use:

MVVS 6,5 GFS/R - ABC - RC Quickie 500 #3068
1,20 kW@ 23000 rpm
372 gr
This engine can be configures as a rear-exhaust
An this for the nice price of 72 Euro's

"quote from website:"
Just AWFULL
At last there seems to be an engine which seems to offer Sport 40 an alternative to the dominant Super Tigre Quickie 500 motor. The MVVS is tested for pulling a 9x7 prop. If it turns less than 17.400 rpm, it is discarded. Most will run right up to 17.700 rpm. The favoured prop for the Tigre is the 9.25x6). Together with Dub Jett's Sport Q500, this is the engine to beat!
"end quote"

Blue Skyy

My Feedback: (3)

Great design! Do you happen to have a shot from the front, especially to see the profile. Doesn't look like much pressure drag there to me!

Blue Skyy

Stuntpiloot

No, sorry. Got no front pic exept the drawing I posted earlier.

The Design is described in an german magazine "FMT"
(FLug und Model Technik) the issue was may 1994.
The plan was also delivered with that issue, and can still be ordered.
building plan nr: MT1090
Name: Vmax

You can order it at VTH in Germany.
The adress I have is:
Verlag fur Technik und Handwerk GmbH
76526 Baden-Baden Germany

I don't know their home page (If they have one)

Stuntpiloot

Found it: www.vth.de

The plan can be found here:

http://www.vth.de/shop/shopfiles/pro...&PS=1&PID=1160

The original plan only costs 9 Euro's