Coro whistling racer

Started by SunLikeStar, December 23, 2011, 10:19:35 PM

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SunLikeStar

Made this racer last month and been having lots of fun with it. The fuse was made with scrap coro at Praddy's place while we were assembling Amar's helli. No designing no plans, just folded coro in a triangle and tapered it for nose and tail. The fuse turned out so good that I decided to complete the plane. The v tail has only elevator control.

SunLikeStar

#1
Wing is from my old easystar for the time being. One inch foam was cut from the root side of both wing halfs and three inch from tips. Both half's were glued together. The initial tip shape was just for testing what I had learned in the aerodynamics thread.
The later pictures show the final wingtip shape. It made tremendous difference, the plane became much more stable and speed just doubled.

SunLikeStar

In pictures one servo for ailerons.
Also there are whistles embedded in the wing ;D Check out the video.

rcpilotacro

Amit ! Superb.
is there any way of reducing the angle of the v tail, a high winger (Since she is inherently laterally stable and wing tip canter adding to it) in which case you will be able achieve 2 things
(a) you will be able to hold the inverted (Presently, as you see,it is slightly difficult in spite of her being slightly tail heavy)
(b) rudder induced pitch (i don't know were you able to make out there is a definite  cross coupling, see MPX Blizzard's design , you will know what i mean)

on the whole super build and wonderful Stuka Bomber Concept (Of whistling)

PS
Over one year you have really come a long way. Kudos
Gusty's Hangar and Introduction.

A Good pilot will practice until he gets it right,
A Great pilot will practice until he can't get it wrong.

SunLikeStar

Thanks for the compliments Augustinev :) I learn from the best :thumbsup:
Yes angle on the tail can be adjusted, i'll try to reduce it. i didnt understand what you mean by rudder induced pitch because i only have elevator on the tail (unlike blizzard).
will update soon with a new coro wing :)

iamahuman

Great job!! I love the sound! It's almost like a dive bomber coming in ;D
"Chuck Norris once overcharged a lipo. Thank him for the Sun."

SSC LCG Slash 4x4.
JQ THE eCar.

SunLikeStar

Thanks!!
yeah its lots of fun! annoys the crap out of everyone ;D which is also fun :giggle:

VC

Great concept and build. Congrats!

How did you embed the whistles? Any photos?

Growing old is mandatory, growing up is optional!

VC

Found some discussion about the Ju 87 and wanted to add my 2 penny bits:

Firstly every dive bomber was a 'Stuka' (shortened from Sturzkampfflugzeug or Dive Bomber). The Ju 87 made this sobriquet most famous.

The Ju 87 didn't whistle on a dive, it wailed. It had a wind driven siren (similar to the hand cranked device that was used to announce an air raid on the ground). The small prop that drove the siren was mounted above the port wheel pant and the pilot could switch it on or off from the cockpit. The sound was primarily meant to unnerve the people near the target.

Here is what it sounded like:



Growing old is mandatory, growing up is optional!

SunLikeStar

Thanks for posting the info VC. One major difference i just noticed while listening to the video is the stuka's sound the pitch variation are huge while my whistle stays on a constant pitch only slight variation due to Doppler effect.

About the whistle, I got them from this frisbee. Carved out foam from the wing and glued them in. Close up of the whistle.

ps: attached picture of the frisbee in case Dx removes it.

VC

Full marks to you for thinking out of the box!

Here are some links on the Jericho Trumpet:

http://www.ww2aircraft.net/forum/aviation/how-make-real-life-size-stuka-siren-16328.html

http://www.rcgroups.com/forums/showthread.php?t=815647

I quote from the first link:

"Mounted on the Ju87, the manual drive was replaced by a suitable alternative, a small propeller driving the unit instead; the variation in pitch here being provided by the Ju87's increase in speed as its dive progressed.

I've an idea Doppler Effect would have been instrumental here, too, particularly if you were the position (or close to the position) being targetted."


Quoted from an entry made by Colin1, a member on that forum.
Growing old is mandatory, growing up is optional!

SunLikeStar

So that's the difference between a siren and a whistle. Learned something new today :)
http://en.wikipedia.org/wiki/Siren_(noisemaker)

rcpilotacro

Quote from: SunLikeStar on December 24, 2011, 11:29:24 AM
i didnt understand what you mean by rudder induced pitch because i only have elevator on the tail (unlike blizzard).

a 'V' tail is essentially two fins with rudder surfaces, cantered, so any elevator movement will have two components, one for pitch and the other one for yaw, since you have a v tail ideally, yaw forces should cancel out, but that is only ideally, in real world it doesn't happen, there is a residual force in the yaw axis (This could be because (a) minor variation in angle of the fins canter (b) uneven airflow due wing / fuse interference,) now this effect can be reduced considerably if you canter only the amount required, more than required canter (Like in your case) will accentuate this yaw effect a lot, sometimes can cause departure on finals if hit by a gust of wind.

PS
I hope i was crisp and clear, if any doubts , don't hesitate to ask
Gusty's Hangar and Introduction.

A Good pilot will practice until he gets it right,
A Great pilot will practice until he can't get it wrong.

SunLikeStar

Got it :thumbsup: yes this has been causing some trouble especially while trying loops & landing. I thought that aligning both control surfaces when in neutral position will fix it but now i see there are other variables. Will definitely reduce the angle now and also thinking about putting in another servo with regular v tail mixing, will be easier to trim that way.