Take a guess...
11-16-2003, 07:39 PM
#1
Take a guess...
So... I have a question for those that want to take a stab at it... How many G's do you think a quickee endures in a hard pull? Let's be specific and say in a TT 40 powered quickee for this example. I've been toying with one at the local club and yanking it around on weekends. Many were asking what the forces were on the plane... I was curious too, so I strapped my telemetry system to the top of the quickee in a box. It slowed it down some because of drag from the box and the additional weight, but there still were some good speeds and hard turns.
I'll let you know what I found out after a few people take guesses. It may or may not surprise you.
Michael
I'll let you know what I found out after a few people take guesses. It may or may not surprise you.
Michael
11-18-2003, 03:18 AM
#15
RE: Take a guess...
Let me first say this.. Very interesting answers! I think most focused in on the area of G's that I saw. Some of you nailed the peak area quite close!
A few notes:
The quickee had an additional 8 ounces onboard with batteries, the box/system,etc. It also had significent more drag and was way slowed down. Altitude data is rough because the static pressure was sensed inside of the box (normally done on the pitot/static). Diving the airplane from 700+ feet was the only way to get it up to 120 ias (indicated airspeed). The setup also did not provide exactly great flying performance as the v-tail was in some dirty air and a lot of airframe buffeting was seen. With some extra time, I could have probably installed all the equipment in the fuselage and eliminated the box, but alas, it was a midnight idea.
Nevertheless, here's a pic of the testbed and some data. One plot shows the g spikes for the entire flight and the other shows two g force spikes along with airspeed and altitude during that time. Max g's seen was 15 entering the turn at 120 mph ias and average turns were 8-12. I tried yanking hard, but in no way was it as hard as I have seen with a clean airframe. I'm willing to bet that 20 G's is not out of the question. Definitely a testament to the strength of the planes that we fly. Average flat and level speed in this flight was 85 mph ias.
Enjoy!
Michael
A few notes:
The quickee had an additional 8 ounces onboard with batteries, the box/system,etc. It also had significent more drag and was way slowed down. Altitude data is rough because the static pressure was sensed inside of the box (normally done on the pitot/static). Diving the airplane from 700+ feet was the only way to get it up to 120 ias (indicated airspeed). The setup also did not provide exactly great flying performance as the v-tail was in some dirty air and a lot of airframe buffeting was seen. With some extra time, I could have probably installed all the equipment in the fuselage and eliminated the box, but alas, it was a midnight idea.
Nevertheless, here's a pic of the testbed and some data. One plot shows the g spikes for the entire flight and the other shows two g force spikes along with airspeed and altitude during that time. Max g's seen was 15 entering the turn at 120 mph ias and average turns were 8-12. I tried yanking hard, but in no way was it as hard as I have seen with a clean airframe. I'm willing to bet that 20 G's is not out of the question. Definitely a testament to the strength of the planes that we fly. Average flat and level speed in this flight was 85 mph ias.
Enjoy!
Michael
11-18-2003, 01:52 PM
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RE: Take a guess...
>>Use less glue..
>>They don't call him "TankPilot" for nothing.
I use Russian design/build methodology.
Forget light and nimble.
I want ‘Takes a Licking and Keeps on Ticking’.
>>They don't call him "TankPilot" for nothing.
I use Russian design/build methodology.
Forget light and nimble.
I want ‘Takes a Licking and Keeps on Ticking’.
11-18-2003, 02:07 PM
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RE: Take a guess...
Actually the weight of the plane doesn't matter. It's all about speed and the radius of the turn. Assuming for example a plane traveling at 110 mph in a 30 foot radius turn would pull 24 G's, increase to a 60 foot radius turn and you get 11.5 G's.
11-19-2003, 03:56 PM
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RE: Take a guess...
ORIGINAL: BasinBum
Actually the weight of the plane doesn't matter. It's all about speed and the radius of the turn. Assuming for example a plane traveling at 110 mph in a 30 foot radius turn would pull 24 G's, increase to a 60 foot radius turn and you get 11.5 G's.
Actually the weight of the plane doesn't matter. It's all about speed and the radius of the turn. Assuming for example a plane traveling at 110 mph in a 30 foot radius turn would pull 24 G's, increase to a 60 foot radius turn and you get 11.5 G's.
I'm creating a Calculations page for [link=http://www.PylonWorld.com]PylonWorld.com[/link] and that would be a handy one to have.
11-19-2003, 05:48 PM
#20
RE: Take a guess...
The general rule, considering the turn is a perfect circle, is Acceleration = V^2/r (velocity squared divided by radius).
Units should be
ft/sec, radius feet or meters/sec, radius meters
A final conversion is also needed where one should divide the result of above by 32ft/s^2 or 9.8 m/s^2
Michael
Units should be
ft/sec, radius feet or meters/sec, radius meters
A final conversion is also needed where one should divide the result of above by 32ft/s^2 or 9.8 m/s^2
Michael
11-20-2003, 09:47 AM
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RE: Take a guess...
>> Actually the weight of the plane doesn't matter.
It does in this scenario.
The weight of the aircraft affects its speed and minimum turning radius.
As the weight increases the maximum G quantity decreases.
If Michael would add a 2 pound weight to the aircraft, the maximum G number would go down a bunch.
It does in this scenario.
The weight of the aircraft affects its speed and minimum turning radius.
As the weight increases the maximum G quantity decreases.
If Michael would add a 2 pound weight to the aircraft, the maximum G number would go down a bunch.
