Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

GP viper and 46FX

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Old 05-03-2006, 05:23 PM
  #1  
afterburner
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Default GP viper and 46FX

Hey guys,
Just need some confirmation on this setup. Will the GP Viper with an O.S. 46 FX with stock muffler exceed a 100mph? Eventually this season(hopefully) I would like to go for a turbine waiver and I need something that will exceed that speed. My Patriot ain't up to the task. Thanks

Marty
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Old 05-03-2006, 08:19 PM
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Super Splatter
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Default RE: GP viper and 46FX

yes, it should go 115 or so. Find some APC speed props. plain old 9x7 are OK, but that Viper will pop with a 8.8x8.75 on a FX

If you put on a AX, then get a plain old 10x7 APC. Goes like stink

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Old 05-03-2006, 09:29 PM
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Default RE: GP viper and 46FX

Is your engine holding the Pat back?
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Old 05-03-2006, 09:43 PM
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Default RE: GP viper and 46FX

Well,
I had the 46fx in it and decided I wanted more speed out of it so I put a Jett 50 in it. I've given up trying to get it setup right. It gets off the ground quicker but doesn't seem much faster in the air. After three minutes of flying it starts hiccuping and it's time to land. I know it's the tank but I'm just sick of working on it.
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Old 05-03-2006, 10:08 PM
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Default RE: GP viper and 46FX

Understood. It just sounds like you may have the worlds slowest Pat, especially considering you tried the Jett[]. Keep trying bro
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Old 05-03-2006, 10:54 PM
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Default RE: GP viper and 46FX

Put the Jett 50 on the Viper, and get a Jett 6oz bladder tank... even faster, and no more hickups.
The bladder tank fits on the CG with minor modifications: you have to move the aileron servo a little to the rear, and you have to use a micro servo for the throttle so it fits under or besides the aileron torque rods.
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Old 05-21-2006, 04:32 PM
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Default RE: GP viper and 46FX

Well,
I figured I would continue on this thread and hope to get a little insight on the Viper.

Was a bit windy all day at the field and after the last person left, I tried a little taxi testing and the 10 X 6 APC wouldn't clear the grass so I went to a 9 X 7 APC on the best 46FX I've ever had. while standing behind the plane I went to about two thirds throttle on high rates and the take off went smooth. Needed a little left aileron and some up elevator which I never got to put in as the plane only flew for another 10 seconds or so before meeting the ground. The bottom line is that it was pilot error for the most part. I had the control surfaces set to what the manual recommeded and had 60% expo on low rates and 80% on high. I didn't switch over to low rates immediately after take off but I was still flying straight out smoothly and then it was getting too far so I started to make a turn and she got squirelly so I switched to low rates and brought throttle down to probably to 1/3. That was probably the big mistake as she slowed and was in a 45 degree dive, I had no elevator response and was to low with trees in the horizon so it dissappeared behind the trees and that was it[:@] Could not find the plane so it's a total loss. I usually don't maiden a plane without someone by my side to give me hand in trimming if needed and I also usually put in a few clicks of up elevator as it's easier to trim a plane that's trying to climb as opposed to diving. I did neither of these things so I only have myself to blame.

My main question on flying this or other pylon type planes is where in the speed range to you go from high to low or low to high rates? Can you cruise at 1/2 to 2/3 throttle on low rates or do you have to keep changing your rates depending on your speed? I'm contemplating buying another one as I have another 46FX laying around. I know I can handle the speed but I just didn't have time to get a handle on the plane before it was gone. Thanks.

Marty


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Old 05-21-2006, 07:39 PM
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Default RE: GP viper and 46FX

If your not "use" to expo, it can kill you. I hate it and only use maybe 20% at most. If I flew with 80%, I may as well fly drunk. At least I would have an excuse for stuffing it. 80% would be way way to sloppy for me.
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Old 05-21-2006, 08:12 PM
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Default RE: GP viper and 46FX

I've been using expo for the last five years and am used to the larger stick movements needed to be effective. I'm not sure about other brands but on Futaba 60% is just enough to smooth out my flying and 80% is for high rates. The percentage sounds high but to me it has just a subtle effect. I'm pretty sure that wasn't what caused my "dumb thumbs" and subsequent crash.
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Old 05-21-2006, 08:28 PM
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Default RE: GP viper and 46FX

If you are using expo, there is no real need to switch between the high and low rates. The plane should respond well in either rate. You may have used too much expo if they are at 60% and 80%, this would make the sticks feel like there is no elev response until you get to near full stick travel. I don't even use that much expo for 3D deflections! The control surfaces are small and don't have much deflection, just use a small amout of expo to smooth out the plane when using small stick movements.

I use a low rate if I want to fly and make turns using full stick movements, but I generally like to fly on high rates with expo.

I do use a landing mode with a little more expo on the elev to let me feather the landing flare.
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Old 05-21-2006, 09:18 PM
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Default RE: GP viper and 46FX

Hi / Low / Expo is all a luxury, not a necessity for a well set up plane. You gotta keep your wits about you and fly with your thumbs. All this other junk is simply over thinking something that is fairly simple. Any Q500 will fly just fine on high rate throws [within reason], low rates is for infinite fine control when you are racing wing tip to wing tip. Forget about all the Ricky Racer stuff, if the plane is built straight, balanced correctly, and has a slop free control system, it will fly just fine with 3/16" + and - travel on all control surfaces at 100 mph [or so].

BTW, dialing in up trim on a maiden is just asking for a stall, it is more intuitive to pull back on the stick than it is to push forward on the stick while you are fumbling for the trim lever.
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Old 05-22-2006, 08:21 AM
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Default RE: GP viper and 46FX


Sorry for the loss there.

Combatpig nailed it there....


There is nothing magical about Q-500 or other pylon planes. Q-500 are by far the easiest to fly - very light wing loading, very simple and slow landings.

You best bet on a Q-500 set up for sport flying, is to set up the control and rates like you would for a sport airplane. Dont go nuts trying to get tons of expo and stuff. Just fly the plane. As long as the CG is set correctly, it will fly like just about any kaos or sportster.

If you have them set up per mfgs recommendations, always take-off on low rates. The high rate throws are there for after engine shutdown when some additional slow-speed control response is desired.

And, with a sport engine, if you wish, take off at half throttle. The plane is pleanty over-powered. Nice straight, level climb - and it will gain speed nicely.
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Old 05-22-2006, 09:08 AM
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Default RE: GP viper and 46FX

Thanks for all the input guys. I have most of my planes set up with expo. Most are set anywhere from 40 to 60% so I'm used to that feel. I don't know why I set the high rates with 80%( Gettin old)? I don't feel it was a contributor to the crash. The main reason was letting it fly out too far before going into a turn. I was trying to get to my trims before making the turn and she got small quick and the lighting at that time of the day at my field didn't help. I have to disagree with CP as if I had put in a few clicks of up elevator before taking off I might have had a better chance.

Bob, I had it on high rates because the manual stated that I wouldn't have enough throw to get off the ground on low rates. I am also flying off grass so I think I needed a little more throw to keep the tail down till she started moving. I think I'm going to try another one. Just wish Tower had the red one in stock for better visibility. I guess I'll throw some colored monokote on the next one.

Marty
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Old 05-22-2006, 09:23 AM
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Default RE: GP viper and 46FX

I loved combattpigs post, he did hit it on the head.

I use low rates for take off and flying, and only high for landing. 3/16" on low rates should be good, although if your use to sport planes with more control it may feel a little sluggish.

Ricky Racer
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Old 05-22-2006, 12:03 PM
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Default RE: GP viper and 46FX

Thanks for all the valueable info. Let me ask another question. Is it SOP to kill the engine on final? Is it more to get the plane to slow down enough or for sparing the prop or both? Thanks.

Marty
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Old 05-22-2006, 12:11 PM
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Default RE: GP viper and 46FX


ORIGINAL: afterburner

Thanks for all the valueable info. Let me ask another question. Is it SOP to kill the engine on final? Is it more to get the plane to slow down enough or for sparing the prop or both? Thanks.

Marty
More to save the prop in my experience. I shut all of the racing planes down for landing.

I land my old scat-cat at idle often enough, even taxi it back. The spinning prop can help slow the plane by virtue of the disk area, but mainly the running engine (as with any aircraft) helps with control and airflow over the control surfaces. I can spot-land that plane as well as my uglystick.
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Old 05-22-2006, 01:06 PM
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Default RE: GP viper and 46FX

Heres a tip that may help. I like make my final approach at idle and once I'm sure its a good one, I hit a switch that I have set up for Throttle kill and land dead stick.

If you don't like your approach, you can throttle up and make another pass at it.
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Old 05-23-2006, 01:21 PM
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Default RE: GP viper and 46FX

Sorry to hear about your loss, it happens though. I've flown a couple of friends' GP Vipers with OS .46 FX's, and
was not that enthusiastic about how they handled. One was definitely tail-heavy on the maiden flight, and was
all over the place, it was all I could do to get it down in one piece. It had a three-blade prop to take care of the
ground clearance problem, but still wanted to nose over on grass; we ended up hand-launching it. The other GP
Viper just didn't want to track accurately, especially on pitch I couldn't get it trimmed to where I was happy, it
just seemed to need constant correction, although the linkages were tight and play-free. Maybe it was also tail
heavy. Quite honestly, most every other Q500 I've flown, (Fliteline Scat Cats, Spickler Quickie 500's, Hobbico
Vipers, Lanier Dominator 500's, Sonic 500's) was way easier to take off and fly than the GP Viper, though I really
do like the GP Viper's slick wing tips and CF reinforced wing. If you don't want to build, the new Lanier Predator
II ARF is probably a good bet.
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Old 05-26-2006, 10:46 AM
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Default RE: GP viper and 46FX

Hi!
I have flown Q-500 (here in Sweden we race with standard 6,5cc engines and 80/20 fuel and standard silencers(not JETT and Nelson)) for some 25 years and never use expo or differential. Instead I always set up my racers so that they behave well with one set up for both racing and landing. This is posible if you balance them out carefully.

Regards!
Jan K
Sweden
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Old 05-26-2006, 11:52 AM
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Default RE: GP viper and 46FX

many times when I am teaching someone how to fly they tell me they have expo. programmed into their tx/plane combo because they read about it somewhere- I remove it (Trainers) and tell them if they do not want to over-control their airplane, learn to move the stick less

This is only on trainers with appropriate deflections, expo is a wonderful tool on many styles of aircraft but should be a supplement instead of a crutch- IMHO

The max I use is 40%, and only on 3D aircraft- I learned to fly before there was expo so that is probably why...

Your mileage may vary!

Cheers
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Old 06-20-2006, 04:31 PM
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Default RE: GP viper and 46FX

Well,
I had ordered another Viper the week after I had lost the first since I had another 46FX sitting on the shelf and I had to prove something to myself. Had to finish up another plane first but I maidened this one this past weekend. Took off on the suggested high rates with some expo( Won't say how much as I don't want to start that again but it was less than the last time). Flew the whole flight at the high rate setting and all went well. Landing went well and second flight was good but on landingm, the plane skidded sideways and the bearing came out of the wheel so that was the end for that day. Looking forward to try a few other props. Those first two flights were with a APC 9 X 7.

Marty
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Old 06-20-2006, 05:27 PM
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Default RE: GP viper and 46FX

Aha! Congrats! ALL because of my advice, yes? (Just Kidding)

I really think most turbine CD's will prefer something like a Patriot with retracts to sign you off for the waiver but if if they will take the quickee then good!

Now put the Jett-50 in the Viper [X(]

Congrats again- you proved you could and it sounds as if you did so easily- Kudos
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Old 06-20-2006, 11:47 PM
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Default RE: GP viper and 46FX

Thanks Razor,
I'll give you credit.

The turbine qualification says that it just needs to be a high performance aircraft capable of sustained speeds of 100mph. Funny thing is, due to a few losses to my fleet this season I pulled out the Patriot in the last few weeks and the Jett 50 seems to be running a little longer per flight without choking and maybe a little stronger as well. Now my flying buddy is telling me that I've got flutter when coming out of a full throttle dive. I'm not hearing it but the rudder does seem to have a fair amount of play in it. Gotta look into that.

Marty
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Old 06-21-2006, 07:35 AM
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Default RE: GP viper and 46FX

All this talk on expo has got me confused. My super 7 Futaba you can have + and - expo what is the difference?


RICH
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Old 06-21-2006, 09:05 AM
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Default RE: GP viper and 46FX

Rich,
On Futaba radios, negative expo makes the stick "LESS" sensitive around center and this smooths out the flying of a plane that might be too sensitive to you. Positive expo would make the plane even more sensitive around the center position. Most of the time you would use negative expo on Futaba. Expo is a personal choice. Some people love it and some don't. I didn't use expo for the first five years I was flying and then I had a plane that was very pitch sensitive. Someone took my radio and programmed in some expo on the elevator and it flew much smoother for me.

JR is opposite of Futaba. I'm not sure about the other manufacturers.

Marty
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