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-   -   Whiplash RIP (https://www.rcuniverse.com/forum/extreme-speed-prop-planes-104/4478122-whiplash-rip.html)

Crazy4Flight 07-08-2006 07:16 PM

Whiplash RIP
 
1 Attachment(s)
Today I had about 8 flights at two clubs on my Whiplash. The Jett FIRE 50 running great!


Severe flutter in a turn at full throttle as usual. Got off the power, and no elevator control it would roll left or right developing a nose down attitude and straight in it went from about 150 feet up. I had over 120 flights on this Whiplash.

Postmortem:
Servo screws on right elevon got loose, two of the screws were gone at the crash site. The Jett 50 was burried 6" deep, carb ripped off, headder bolts ripped out, tuned pipe impaled on the headder. Switch was torn out of the MPI switch/charge unit. Receiver case popped open a 9 ch PCM. Airframe is totaled...Jett 50 will go in for a case and bearings. Rx will get sent to Futaba for evaluation.

cobratraxxas69 07-08-2006 08:45 PM

RE: Whiplash RIP
 
Sorry to hear that.....Is that a 3X9 prop you're running now?? :D

How fast do u think it was in straight and level, as that is a great engine/plane combo??

combatpigg 07-08-2006 08:49 PM

RE: Whiplash RIP
 
C4F, One of the cruelest realities in our universe is that screws aren't self tightening, they always work loose. Sorry for your loss, but thanks for the wake up call. The problem is that we are all pressed for time to have fun, and don't want to do the boring job of checking everything. Of course, there are certain things that go wrong that routine checks won't reveal.
I don't know anything about Whips, you said you had flutter AS USUAL at full throttle?

Razor-RCU 07-09-2006 12:16 AM

RE: Whiplash RIP
 
I have never heard of flutter on a Whip---

Cyclic Hardover 07-09-2006 01:07 PM

RE: Whiplash RIP
 


ORIGINAL: cobratraxxas69

Is that a 3X9 prop you're running now?? :D
Sorry for your loss but a 3/9? Thats funny.

MJD 07-10-2006 10:23 AM

RE: Whiplash RIP
 
Mine is almost ready to go.. I'd sure like to hear about this! What servos were you using, and what did you install for pushrods?

Ouch, you sure broke it.. sorry about that. PITA + $$$!

MJD

deckerv 07-10-2006 12:52 PM

RE: Whiplash RIP
 
Mine did the same thing once upon a time.. luckily it went straight into a freshly plowed/damp field, so the only damage was a broken motor mount. I since fixed it with a couple carbon fiber rods going from the front of the mount to almost the radio compartment. Good as new, and still flying like a champ :)

I do however now put a very small amount of blue locktight on the servo arm screw now. Mine was a Hitec digital.. how about yours? Sorry for the loss man.. that's sad :(

Razor-RCU 07-11-2006 12:41 AM

RE: Whiplash RIP
 
MJD- I have flown several the first 2 with Hitec-645MG's on 6V (133 Oz.) my current one with Hitec 5645 digis (168 oz @ 6V)... Been lucky so far-

MJD 07-14-2006 10:01 AM

RE: Whiplash RIP
 

ORIGINAL: Razor-RCU

MJD- I have flown several the first 2 with Hitec-645MG's on 6V (133 Oz.) my current one with Hitec 5645 digis (168 oz @ 6V)... Been lucky so far-
I bought HS-945's for mine, 122 oz-in at 4.8V, 153 at 6V. Probably going to use a 6V 1100 mAH pack since I have a bunch of those cells around for my park fliers.

However - without having seen the warnings some people have made about metal gears on high rpm applications, I bought 945MG's. Thought I was doing the right thing. Others have said not to worry, go ahead and use them. Now I am tetterinjg on the decision. Hitec said they've never heard of such a recommendation.

Any sage advice on this Revvers?

MJD


MJD 07-14-2006 10:05 AM

RE: Whiplash RIP
 

ORIGINAL: MJD
Probably going to use a 6V 1100 mAH pack since I have a bunch of those cells around for my park fliers.

... Now I am tetterinjg on the decision. Hitec said they've never heard of such a recommendation.

Time to hit the Mavis Beacon Typing Tutor again.. that word was supposed to be "teetering".

The Rx pack I plan to use is 6V 1100 mAh NiMH, so no heavier than 500-600 mAh NiCAD, plus these are 1C charge rate cells so field top up is a snap.

MJD

Razor-RCU 07-15-2006 01:27 AM

RE: Whiplash RIP
 
I have not experienced or heard of problems with MG servos on a speed plane... It would be difficult to get the necessary torque for the Whip without MG servo's [X(]

MJD- What are you puttin' up front?

HaveBlue 07-15-2006 09:24 AM

RE: Whiplash RIP
 
I'm in the same boat, a few have told me never to use metal gear servos for speed applications, the meshing isn't tight enough, or so they say, but I dont know what else to use with the stiff elevons of a whip..

Hitech advertise tighter messing( I'm sure I read that somewhere) on there titanium geared servos, but even so flutter is hard to imagine on a whip ..C4F mentioned " the usual flutter" that made an eyebrow raise , cause I would never think that it could happen on a whip...maybe they loosen after several flights or something..I dont know, I haven't flown the whip I have , nor built it for that matter

guess I'll have to wait to hear how you guys do. My club has just banned IC engines..I had plans to get a 60LX fire for the whip..thinking of giving the whole game away as the cost of replacing all my glows for electric set ups is beyond my affordability...this really sucks as I've got a fair few "nice" engines..now I cant use them[:o]

Razor-RCU 07-15-2006 12:27 PM

RE: Whiplash RIP
 
Banning IC's? Holy cow! That sucks...

I would have to see the flutter to believe it... Heck I wish the elevons were LOOSE enough to possibly flutter. I would get some digital nylon geared servos like they use in pattern, but again I have not had any problems with the 645's or 5645's :D

Can you fly at a different location?

Sorry to hear that mate!
James

P.S. What does "Aussie, Aussie, Aussie, oy, oy, oy" mean?

HaveBlue 07-15-2006 05:17 PM

RE: Whiplash RIP
 

ORIGINAL: Razor-RCU

Banning IC's? Holy cow! That sucks...

I would have to see the flutter to believe it... Heck I wish the elevons were LOOSE enough to possibly flutter. I would get some digital nylon geared servos like they use in pattern, but again I have not had any problems with the 645's or 5645's :D

Can you fly at a different location?

Sorry to hear that mate!
James
I never thought 1 noise complaint could cause so much hasle...they are looking at other locations..so i'm holding off before I flood fleabay with a long list... though the way petrol prices are escalating ( approx $5.14 a gallon) and the urban sprawl, flying sites are getting hard to come by...can't wait to retire ..I'll buy a house in the country on some acerage!!!!


ORIGINAL: Razor-RCU

P.S. What does "Aussie, Aussie, Aussie, oy, oy, oy" mean?
[link=http://en.wikipedia.org/wiki/Aussie]look here[/link]

and as for the servos my alternative is a couple of HS6985hb...karbonite gears and 172oz @6v...only problem is their 116 bucks a pop...ouch!!!!


Razor-RCU 07-15-2006 10:11 PM

RE: Whiplash RIP
 
Thanks Blue! I was just at a "Brazilian" BBQ and in Portugese Oi! Means hello... Good stuff here on our multi-cultural message board!

You get ripped living in AUS with prices--- $116 is quite a bit...

combatpigg 07-16-2006 12:43 AM

RE: Whiplash RIP
 
The carbonite gears of some HITEK servos might be the best option. The metal gears get back lash from high revving vibration. I have never seen a WHIP in person, but it seems you could work those flaps around enough [by hand] to loosen them up. In a real speed application, [not a hot doggin' plane] you don't need much flap travel or servo power for that matter. A stiff, slop free control linkage is the most important thing. Carbon tubing slipped over 4-40 pushrods that are secured to the push rods with Gorilla Glue work for me.

BAGOSTIX 07-16-2006 06:01 PM

RE: Whiplash RIP
 
Unfortunately, vibration is only good for a few things in life..
one of them aint airplanes..
sorry for your loss... fyi, gettin closer to production on the Whip..
[8D]

Razor-RCU 07-16-2006 07:29 PM

RE: Whiplash RIP
 
Combat- The Whips Elevons are VERY stiff and working them by hand loosens them minimally. It has not been a problem for me (and I've had 3) it just makes me feel uneasy ;) ACM includes good hardware with CF rods and ball link ends-- :D

I will continue to use 645MG's or the Digital 5645's, and I cannot wait to get ahold of another WHip and a couple more shaker cans of paint!

crasharama 07-17-2006 03:37 AM

RE: Whiplash RIP
 
Hey guys,

I have also hear dthat the Karbonite gears crack & let go with high vibration. With the rev's we pull, maybe they aren't a real good choice either.

Razor,

Aussie Aussie Aussie, is usually at a sporting match, but

'cmon Aussie c'mon,
c'mon

Is from an old ad for 1 day cricket, if you are at an international 1 day game, you can hear the crowd singing this too :D

www.cricket.com.au
Tony

MJD 07-17-2006 03:58 PM

RE: Whiplash RIP
 

ORIGINAL: Razor-RCU

I have not experienced or heard of problems with MG servos on a speed plane... It would be difficult to get the necessary torque for the Whip without MG servo's [X(]

MJD- What are you puttin' up front?

Jett .50 FISE. Not a .60LX FIRE, but it will do the job just fine for me, at least until my next eye appointment and new prescription.. [8D]

I'll put on the 645MG's. If I have a problem at least it will be another data point to ponder.

CP - that's how I made the pushrods for this and a few other aircraft, with the exception that I cleaned the rods with MEK, then wicked thin CA between the two. Gorilla Glue is great stuff - the other retail version is ProBond PolyU adhesive. Love 'em. It makes good sense - why get spot adhesion and extra weight with a dense resin system when you can generate foam to fill all the voids and bond to a greater overall surface area.

MJD








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