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HomeAircraftHelicopterThunder TigerOther › Inverted Auto - spinning out on pushover
05-08-2005 07:19 PM  13 years agoPost 1
flyanything

rrApprentice

Tallahassee, FL

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I started doing inverted autos about a month ago. My first ones were my best ones... climb out to very high altitude, pull elevator up to flip it back toward myself, click throttle hold keeping almost full positive pitch, make rudder and elevator adjustments to keep it coming in straight and slightly nose up, then at about 50 feet or higher I start pushing over with down elevator and start taking out positive pitch. When the disk is about perpendicular with the ground I'm passing through zero pitch. Then as the push over completes I'm putting in full negative pitch and bringing it in tail first... no problems. Ok, here's the question: this was working great on my Raptor 50SE with TT 600 carbons but every time I tried it on my Raptor 50v2 the heli would go into a spin as soon as the pushover got close to upright. I had somebody watch my sticks to make sure I wasn't putting rudder inputs during the pitch change. I thought the tail was just letting go. So I only did the inverted autos on my 50SE (both helis have GY401/9254). Well, now my 50SE is doing the same damn thing... spinning wildly on the pushover to the point where I have to click out of EVERY attempt. I tried replacing the tail blades with some wider Mav 85mm carbons but no change. My tail only lets go once in a while when doing very fast backward flying. I haven't noted which direction the spin takes as I'm too occupied trying to get the heli level and click out of throttle hold. I'll have somebody watch it today and update this question. But does anybody know what can cause this bigtime spinning?

Thanks,
John

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05-08-2005 08:13 PM  13 years agoPost 2
Wes Crockett

rrApprentice

Bourne End, Buckinghamshire, UK.

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This may seem pretty obvious, but have you checked to see if your in heading hold when you flick into throttle hold? Also double check that your running the same amount of gain in the throttle hold condition.

Noticed from your profile your using a 9CHP which has different gyro settings for each flight mode so its pretty likley thats where your problem lies.

If your still getting problems its probably worth changing over to 95mm V-tailblades, can't see you having a problem after that.

Wes

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05-08-2005 08:34 PM  13 years agoPost 3
stevengerrard

rrVeteran

Wigan NW of England

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also have you checked your one way auto unit to see if it is working freely???

if not it is likley to be talking lots of your head speed and also tail speed.....

if you slow the head speed up to much then the tail will not be spinning fast enough for the gyro to work......


Hope this helps


Steven Gerrard

CarbonXtreme
AvantRC
V Blades
Magnum Fuel
Align
Spektrum
Thunder Power

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05-08-2005 11:55 PM  13 years agoPost 4
A. Bundy

rrElite Veteran

Aurora,IL. 30W/SW of Chicago

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My tail blows out like that only when I get the head speed too slow.The smoother the flip,the more solid the tail stays.

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05-09-2005 04:00 PM  13 years agoPost 5
flyanything

rrApprentice

Tallahassee, FL

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Wes, checked my gyro sense and it is set for 75% heading hold (AVC)in all three flight modes (switch E). Will the 95mm V-tail blades clear with the 600mm V mains?

Steven, yep, auto gear is spinning freely... and regular autos are a breeze... lots of hang time.

Bundy, you may have a good point... I've been getting more and more aggressive with the pushover and maybe it's just getting too fast to keep the blades spun up. I will try to smooth it out and see if that helps.

Thanks for all the good suggestions.

John

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05-09-2005 07:28 PM  13 years agoPost 6
Wes Crockett

rrApprentice

Bourne End, Buckinghamshire, UK.

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Hi John

No problems with your radio settings then. Although I don't have a raptor 50 myself, most of the guys at the field I fly at are running the 95mm V-tailblades with 600mm blades on their raptor 50's and havnt experienced any clearance problems but you might want to double check for yourself that they're ok with the V mainblades.

P.S I'm running the 95mm V-tailblades on my evo and tried lots of other tailblade makes/lengths. The V-tailblades get my vote and provide awesome tail holding power providing your gyro is setup correctly.

Wes

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05-09-2005 10:49 PM  13 years agoPost 7
A. Bundy

rrElite Veteran

Aurora,IL. 30W/SW of Chicago

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I have hit 95s several times.Only in really hard moves.

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05-13-2005 05:15 PM  13 years agoPost 8
flyanything

rrApprentice

Tallahassee, FL

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Smoother but still letting go...
Ok. I tried smoothing out the pushover and it did help get the heli pushed over further to backwards-upright with no heading change... BUT... as soon as it gets into tail-in the tail lets go and it does a 180 to nose in. I asked another advanced pilot at our field, who does inverted autos all the time with a R50, to try it on my model. The same exact thing happened to him... smooth, straight pushover but tail lets go during tail-in decent. He did it several times and was baffled.

So, I'm thinking that these are some of the possibilities:

1. Tail servo is starting to wear out (can try a new servo to eliminate this one)
2. Gyro issue (have a spare JR500T I could try)
3. Tail blades not providing sufficient tail authority at lower auto headspeed. (can try 95mm just to eliminate this one)
4. Switched from heavier TT 600mm carbon to 600mm V-blades and lighter blade is not holder as much headspeed during autos. (switch back to TT carbons and try it)

What really bugs me is that I was doing inverted autos with no problems for a while and now this problem has been keeping me from away from them and making me nervous whenever I'm doing anything backwards.

So, I guess I have some troubleshooting to do. If you guys can think of other things I should try let me know.

Thanks,
John

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05-13-2005 06:31 PM  13 years agoPost 9
SolarXtreme

rrVeteran

Arroyo Grande, CA

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Remember there is no torque present in an auto. There is only two things that can cause the tail to swing around:

One the tail rotor is telling the tail to move one way or the other via user input or gyro/servo problem. If the tail swing is ending up in a random position evertime this is your problem.

Two the tail is weather veining. If you are flying it in tail first and it comes around nose first then this is more then likely your problem. Could be loose tailbelt or something wrong with your driven tail.

Also try rolling out of the auto instead of flipping and see if the problem persists.
.

I picked a hell of a day to quit drinking

Avant EFX
Freya EVO

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05-13-2005 10:29 PM  13 years agoPost 10
MJA

rrKey Veteran

UK

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<

One the tail rotor is telling the tail to move one way or the other via user input or gyro/servo problem. If the tail swing is ending up in a random position evertime this is your problem.

Two the tail is weather veining. If you are flying it in tail first and it comes around nose first then this is more then likely your problem. Could be loose tailbelt or something wrong with your driven tail.

>>

I agree with all of that but would add a third to the list,not neccesarily
as the cure
for the turnaround problem he's having now ,but i took it to be that it was during the pushover but now it seems to be at the start of the backwards approach

Three

If you load up the rotor disk very quickly ie so it makes
it lose nearly all it's stored headspeed quickly
it can try to take the body of the heli around in the same direction as the main disk.Even on a slipper or full driven tail if the tailspeed drops too low at the same time,which it does,the tail won't be powerful enough
to be able to stop it

On a belt driven tail heli this is more likely to happen as the same drag that makes the blades slow down quicker in comparison to a tube drive tail,
will be the same extra
drag that tries to turn the body of the machine around
with the rotor direction
A tight auto unit tends to do the same thing or the drag in the mainshaft bearings.On a Raptor 50 having the belt too tight will make that worse as it side loads the mainshaft and auto unit more.

Unless you are doing almost on the deck pushover recoveries,
where you don't want to back the heli in
for the landing from any height or distance , it's best to keep at least 0 deg collective and
even add more positive when you see the top of the disk flat into the airflow/wind

(especially if it's windy with the top of the disk into wind during the pushover,it'll need a bit more positive
) ie when the heli is getting full nose high/tail low

This helps with the headspeed loss you get when adding the cyclic to flip it over ,at the point when the heli is presenting the top of the disk into the airflow/wind
and won't bring the heli to a dead forward speed stop
in the air as much.

Has this heli got a fully driven tail?
Only reason i ask is a slipper tail that's not set very tight
will weathervane before a driven tail when the headspeed/tailspeed gets low


Martin

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