First SPAD: Racer design

First SPAD: Racer design
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First SPAD: Racer design - 8/31/2007 6:30:27 AM

IL2windhawk

Posts: 387
Joined: 4/7/2006
From: Ogden, UT, USA
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This is my first attempt at SPAD in general, but also to designing & scratchbuilding.

It has a 40" wingspan. E-flite 15 motor. It weighs 40 ounces, for a 0.15oz/in2 wingloading (eek

)
Should be plenty fast, I figure! Anyway, I'm gonna try to fly her this weekend.

EDIT: Oh yeah, and it's painted up like Jimmie Johnson's 48-car per my girlfriend's request.

< Message edited by IL2windhawk -- 8/31/2007 6:33:05 AM >

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RE: First SPAD: Racer design - 8/31/2007 6:41:59 AM

NikolayTT

Posts: 575
Joined: 9/29/2002
From: Tampere, FINLAND
Status: offline

Looks nice, congratualtions ! Couple comments: - The speed might be decreased much by the wings thickness
and the wheels, maybe smaller wheels or no wheels at all would be lot better. And also, you are happy guy - your
girlfriend does not hate(yet) the RC things, better teach her to fly RC as soon as possible ... then you will
be even more happy in the future than most of us ...
Cheers,
Nick

< Message edited by NikolayTT -- 8/31/2007 6:43:29 AM >

(in reply to IL2windhawk)

Post #: 2

RE: First SPAD: Racer design - 8/31/2007 7:06:34 AM

IL2windhawk

Posts: 387
Joined: 4/7/2006
From: Ogden, UT, USA
Status: offline

Thank You for your compliments. Yes, my G/F is excited to learn RC flying.
I was actually trying to make this a trainer to teach her, because she wants
to learn, but I'm afraid that this plane will be too hot to learn on. I hope to
take the lessons I learned from this one to make a nice trainer next time.
Then she can crash it and it won't matter cause it's a scratch-build job.

Yes, I immediately wished that I had made the wings thicker. As for the
wheels, well they are foamies so they only weight about 5 grams each.
I suppose they will create drag, but I need big wheels to land on grass.

Oh yeah: since the photos were taken I fixed the twist in the tail section.

< Message edited by IL2windhawk -- 8/31/2007 7:08:02 AM >

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RE: First SPAD: Racer design - 8/31/2007 8:08:06 AM

NikolayTT

Posts: 575
Joined: 9/29/2002
From: Tampere, FINLAND
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Although your fuselage is not completely aerodynamic, the biggest drag I guess will come
from the wings. Also take-off from hand and landing on a grass is OK without wheels might
prove how huge the effect of the wheels is - I did that just to test and after that I am trying
to avoid wheels at any cost. That is not only their drag, it seems to me that drag comes in
"right" place to damage every thing even for very big and powerfull planes.

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Post #: 4

RE: First SPAD: Racer design - 8/31/2007 9:42:51 PM

TruBlu02

Posts: 277
Joined: 1/3/2004
From: Cabot, AR, USA
Status: offline

Very cool little plane I would be interested to to hear how its maiden goes. If it flies well you should submit the Plans to www.spadtothebone.com and maybe they will be included in the free plans list.

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Post #: 5

RE: First SPAD: Racer design - 9/1/2007 6:21:22 AM

O2man

Posts: 212
Joined: 4/5/2003
From: Selah, WA, USA
Status: offline

Good looking build! I salute your courage in using the brown stuff for fuse formers. I can't be the only one looking forward to the maiden flight.

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Post #: 6

RE: First SPAD: Racer design - 9/2/2007 5:52:44 PM

Smooth Spanky

Posts: 154
Joined: 9/24/2003
From: Shelby Township, MI,
Status: offline

Very nice looking plane, IL2windhawk. I hope things go well with the maiden flight.

Smooth

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Post #: 7

RE: First SPAD: Racer design - 9/3/2007 8:17:06 PM

IL2windhawk

Posts: 387
Joined: 4/7/2006
From: Ogden, UT, USA
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Well fellas, I have a maiden report.

The first flight was incredibly difficult! First, the nose landing gear bounced like crazy!
I think I bounced off the runway twice before I was airborne! Then, the control throws
were set about 3 times higher than optimal. At first, I thought the plane was inherently
unstable and unflyable, but then I switched the low rates on and was able to get some
degree of control over the aircraft. I flew a few circuits to set the trim (which was
significant, I regret to report), and then I brought it in to adjust the control throws.
The landing resembled the takeoff, with lots of bouncing, ultimately topling the plane
but causing no damage.

I then reduced the control throws, recharged batteries, and set off for another flight.
The take off was difficult once again, but this time when the plane went airborne, it flew
magnificently. It was smooth and fast. I did a few loops, and then some stall
tests which revealed a nasty tendancy for a left tip stall. Unfortunately, the flight ended
with some sort of interferance problem that caused a crash. I was able to regain control
just before impact, which minimized damage. Really, everything was fine except that the
firewall was knocked out. The components are visually fine, but testing will follow.
I should be able to repair the plane in a couple hours.

I imagine that there will be at least one improvement: a new tail-dragger landing gear
configuration. Then I can add steering off of the rudder. Secondly, I'm considering the
addition of a second wing to make it a bi-plane, which would reduce the wingloading.

quote:

ORIGINAL: O2man

Good looking build! I salute your courage in using the brown stuff for fuse formers. I can't be the only one looking forward to the maiden flight.

Thanks for the compliments. I was kinda wondering how my use of basswood is "courageous".
Are you just saluting my build technique, or am I taking some risk that i should know of!
Please clarify, Thanks.

Post-Flight: firewall missing, some chipped paint.

< Message edited by IL2windhawk -- 9/3/2007 9:11:03 PM >

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RE: First SPAD: Racer design - 9/3/2007 9:38:25 PM

O2man

Posts: 212
Joined: 4/5/2003
From: Selah, WA, USA
Status: offline

Windhawk,

My Tongue-in-cheek comment is based on the razzing you may take using anything not plastic in construction of a SPAD. There are a few out there that are intolerant of wood in any form.

Sorry to hear of the difficult first flight. Experimentation can be time consuming, not to mention frustrating. Ultimately you will have something special. It looks good already.

Try either a conventional factory nose gear, or the lighter rudder activated tailwheel. The wire you first built is destined to bounce, as you noticed. I am willing to bet that you will find the extra wing likely to interfere with your racer aspirations. Speed implies a certain amount of wing loading. Extra wing area makes less wing loading but lots of drag to go with it.

I wait with baited breath to hear of your further exploits.

By the way---neat bunnies on the kitchen table.

< Message edited by O2man -- 9/3/2007 10:48:26 PM >

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Post #: 9

RE: First SPAD: Racer design - 9/4/2007 9:16:48 PM

IL2windhawk

Posts: 387
Joined: 4/7/2006
From: Ogden, UT, USA
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Those "non-wood" fellas must be real extremists.

Thanks for the encouraging words, but the first two flights were some one of the
most fun I've ever had at the field. I think I only would have been disapointed
if I had lost components after that crash. I had to look for the motor for a while.

I've already decided against the bi-plane idea. I wil probably will leave it be after
I fix the nose gear, and then I will make a biplane from the ground up.

Pink bunnies! Ha!

I've honestly never looked close enough at that table cloth to realize what was on it.

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RE: First SPAD: Racer design - 9/6/2007 7:04:22 PM

OzMo

Posts: 1440
Joined: 9/2/2002
From: OZark, MO, USA
Status: offline

HEY nice bird

"that brown stuff" is "organic corplast"

SPAD rule #1 "Use what you got"

Just a thought or two:
changing to tail dragger...good idea
chnging to biplane.....ooooh watch the wieght

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Post #: 11

RE: First SPAD: Racer design - 9/8/2007 12:44:30 PM

Smooth Spanky

Posts: 154
Joined: 9/24/2003
From: Shelby Township, MI,
Status: offline

Windhawk:
Sorry to hear about the trouble with the first flights, but it sounds like you are working out the bugs. Good luck with the changes, and just keep having fun.

Smooth

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Post #: 12

RE: First SPAD: Racer design - 9/10/2007 4:52:38 AM

IL2windhawk

Posts: 387
Joined: 4/7/2006
From: Ogden, UT, USA
Status: offline

I've put another few flights on her, and now I've worked out most of the kinks.
Although I fixed the nose-wheel bounciness, I had problems getting the landing gear
to track straight, so I eventually decided to remove the wheels when I found a folding
prop that worked. I flew it twice today in this configuration and it was a nice setup.
Hand-launching was a little dicey though (due to the high wingloading). I will always
have to hand-launch from at least a small hill.

The E-flite 15 flies it around at a fairly good clip with about 65% throttle. I got a 10-min
flight today on a 2000mah battery. Not a bad flight time for electric, and i think I could
stretch that by a couple more minutes.

I've had such a blast scratch-building a plane. I've taken the lessons learned and I've
started working on a second spad. This time I will build fuselage first, then wing after
i know the final fuselage weight. I think I did things a bit backwards on the first plane.

Cheers

< Message edited by IL2windhawk -- 9/10/2007 4:56:50 AM >

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RE: First SPAD: Racer design - 9/10/2007 1:43:17 PM

TruBlu02

Posts: 277
Joined: 1/3/2004
From: Cabot, AR, USA
Status: offline

Looks cool man. You can't beat using coro to experiment. Making repairs or improvements is so much easier when you can just lay down the sheet and knock out a new piece with the utility knife. I know I had to do alot of experimentation in tail design when io converted one of my SPAD's to floats. I probably went with 5 different tail sections before I found one that was a good balance for the plane.

(in reply to IL2windhawk)