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-   -   How fast do you think it goes? (https://www.rcuniverse.com/forum/extreme-speed-prop-planes-104/1149120-how-fast-do-you-think-goes.html)

schmleff 09-19-2003 11:31 PM

How fast do you think it goes?
 
1 Attachment(s)
I have been flying this design for a few years. Here are the specs and picts. It was not really built for speed alone, but high speed radical control throw aerobatics.

How fast do you think it might be?

Span: 44"
Chord: 10"
Length" 41"
Weight: 5.25 lbs.

Power: OS FX .46
Prop: APC 9x7
RPM static: 15880
Speed: ???
Climb: almost unlimited.

ChuckAuger 09-20-2003 12:22 AM

RE: How fast do you think it goes?
 
I'd say about 90 mph.

LGM Graphix 09-20-2003 12:43 AM

RE: How fast do you think it goes?
 
chuck would be my middle ground, I figured 80 to 100mph.

schmleff 09-20-2003 08:42 AM

RE: How fast do you think it goes?
 
I am going to have to mount my gps in the turtle deck and check it out. I have always thought it would do about 100-110 straight and level and about 130+ in a dive.

The only reference I have for speed is the last time I strapped my gps to a supersportster bipe and recorded speeds over 100mph.

daven 09-20-2003 06:21 PM

RE: How fast do you think it goes?
 
Its the weight thats hurting you, but I would still think you could hit 100 mph with it, and possibly 110.

Windwalker 09-20-2003 08:32 PM

RE: How fast do you think it goes?
 
Nice design-What is it?
Have you thought about sweeping the wing rearward to increase speed or looks?

schmleff 09-20-2003 10:17 PM

RE: How fast do you think it goes?
 
It is just my creation. It was an experiment really. The second of its type. The first was built out of junk that was given to me or I scraped out of the field dumpster. This one was built from scratch. I just call it the "Frankenplane"

The goals were as follows:
fast
land slow
be very tough (able to withstand mishaps)
be able to use full control throws at maximum speed
try to see how wide of a speed range I could make it operate in
fit in my car without taking it apart

The airfoil is pretty thin really with a sharp leading edge. The forward sweep is only there to make up the the leading edge induced abrupt stall. It does not tip stall. lands quite slow.

Sweeping the wings back would do little to improve speed, just make the stall worse. As for the looks, i have gotten used to the fsw.

It is heavy because the wing is wood with glass laminate to be strong enough to take the extreme stress that I wanted to put it through. Since the induced drag goes down with the square of the speed, I really don't think that that is the major thing that keeps it from being really fast. The fuse is to big with to much frontal area, but it is really an aerobat. I wanted to be able to knife edge it.

It really is strange when I bring it down on the deck, pull up and put it into a snap roll. It becomes just a blur of black and yellow. It rolls about 4 rolls per second with just aileron.

Anyway, thanks for the compliment.

Schmleff

Gordito Volador 09-21-2003 01:12 AM

RE: How fast do you think it goes?
 
What model GPS are you thinking of using? I have a small Garmin that I think will not add too much weight to my planes for speed checks.

schmleff 09-21-2003 09:00 AM

RE: How fast do you think it goes?
 
I have a garmin xl-12 I think. It is the one that sells for about $150.

I rubber banded it to the little biplane between the main top wing support. I cant really get it to stay on my plane so I will have to take tweety out and mount it under the canopy and turtle deck.

Schmleff

LUDS96 09-23-2003 08:04 PM

RE: How fast do you think it goes?
 
My Garmin GPS 12 goes blank on top of the Plane RF or Rattle but it won't read!

schmleff 09-23-2003 09:17 PM

RE: How fast do you think it goes?
 
Hmm. I use it in my full scale Sonerai and it works well. I have had it over 180mph without problem, over 600mph on an airliner without problem.

Schmleff

LUDS96 09-24-2003 11:29 AM

RE: How fast do you think it goes?
 
Go figure! I've had it in a real plane no problem! I put it on top of a model and it goes blank!!!

DTB 10-20-2003 08:45 PM

RE: How fast do you think it goes?
 
The formula states it is should go 105.26 MPH.

aerobat66-RCU 10-22-2003 10:57 AM

RE: How fast do you think it goes?
 
I would agree with DTB for a ballpark number.

(RPM x Pitch) / 1056 = 105.26 mph

The engine unloads some in the air, but there's also drag to consider. I've compared calculations with radar on a Lanier Shrike, and they were within 3-4 mph of each other.


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