New RC World Speed Record - 545MPH! - RC Groups

New RC World Speed Record - 545MPH!

This past Saturday a new world speed record was set by pilot Spencer Lisenby at Bird Spring Pass. He was flying the Transonic DP and reached a staggering speed of 545MPH!!

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Fastest RC Plane in the World!

By now, most of the RC community should know about dynamic soaring or DSing, where a non-powered sailplane is flown in an elliptical loop on the back side of a slope. It allows the plane to continuously increase in speed with little resistance. The higher the wind speed, the faster the plane can fly. Airframes had to be re-designed to handle the stresses, but it's really neat how the fastest RC planes in the world have no power systems. RC Turbine jets can't even come close!

This past Saturday a new world speed record was set by pilot Spencer Lisenby at Bird Spring Pass. He was flying the Transonic DP and reached a staggering speed of 545MPH!! That is incredible, but theory suggests that speeds can be pushed even further. It's amazing to watch and huge kudos to the camera man for keeping up. Watch the video below to see the new RC world record flight.

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Jun 13, 2018, 02:01 PM
Registered User
That's amazing! At some point wouldn't swept wings allow for even greater speeds?
Jun 13, 2018, 02:04 PM
Brett
bjaffee's Avatar
Quote:
Originally Posted by Bballreich
That's amazing! At some point wouldn't swept wings allow for even greater speeds?
I know Spencer has experimented with swept wings, but I don't think he's quite been able to get them to work how he wanted.
Jun 13, 2018, 02:17 PM
Everything's A Compromise
Larrikin's Avatar
Quote:
Originally Posted by Bballreich
That's amazing! At some point wouldn't swept wings allow for even greater speeds?
Swept wings for straight line speed.
Straight, high aspect ratio wings for turning performance.
Everything’s a compromise.

D.
Jun 13, 2018, 03:31 PM
B for Bruce
BMatthews's Avatar
And given that the models are turning in a looping path that is generating 30G or more a wing setup that can best carry the load is a key requirement too. And I believe that the straight wings also provide less drag at the lift values needed to hunker down against all those G's.

It won't be long at this rate before the wings at least begin to experience transonic effects.

A hearty CONGRATULATIONS ! ! ! to Spencer and his team.
Jun 13, 2018, 05:17 PM
resU deretsigeR
LDGILLS's Avatar
Ah.... Wow...... Just simply..... Wow......
Latest blog entry: My TR-260 second flight.
Jun 13, 2018, 07:32 PM
Registered User
sll914's Avatar
Quote:
Originally Posted by BMatthews
And given that the models are turning in a looping path that is generating 30G or more a wing setup that can best carry the load is a key requirement too. And I believe that the straight wings also provide less drag at the lift values needed to hunker down against all those G's.

It won't be long at this rate before the wings at least begin to experience transonic effects.

A hearty CONGRATULATIONS ! ! ! to Spencer and his team.
Thank you!

Yes the wing is already experiencing transonic conditions. We even have already had locally SUPERSONIC flow over the upper wing surface. Dr. Drela provided some plots a few years ago showing local flows around m=1.2 when freestream velocity was m=0.65. As a result, the wing on the Transonic DP was specifically tailored to reduce these local velocities and delay the formation of lambda shock waves that cause a huge increase in drag.
Jun 13, 2018, 08:11 PM
"I will return" Federico
rclad's Avatar
This is science for the pure fun of it. An awesome achievement! And to think that the humble Albatross figured it out long before we did.
Jun 13, 2018, 08:20 PM
resU deretsigeR
LDGILLS's Avatar
Quote:
Originally Posted by sll914
Thank you!

Yes the wing is already experiencing transonic conditions. We even have already had locally SUPERSONIC flow over the upper wing surface. Dr. Drela provided some plots a few years ago showing local flows around m=1.2 when freestream velocity was m=0.65. As a result, the wing on the Transonic DP was specifically tailored to reduce these local velocities and delay the formation of lambda shock waves that cause a huge increase in drag.
Incredible. Do you plan on supersonic flight?
Latest blog entry: My TR-260 second flight.
Jun 13, 2018, 09:21 PM
Registered User
Just stunning , you D/S guys are the best !!!
Jun 13, 2018, 10:48 PM
Registered User
I have nothing to do with this achievement. However, according to what I've been reading, there are some real challenges getting from 545 mph to supersonic. For instance, 545 mph is around Mach .71, but data I've seen on drag of other aircraft show a dramatic rise in drag as the Mach number gets a little higher than this. Figures I've seen for the L/D of supersonic aircraft top out in the vicinity of 7 or so, though there are schemes for doing somewhat better in the future. Is dynamic soaring really possible with such low L/D's? Is a hurricane necessary? If so, the pilot may have some difficulties!
Quote:
Originally Posted by LDGILLS
Incredible. Do you plan on supersonic flight?
Jun 14, 2018, 02:07 AM
B for Bruce
BMatthews's Avatar
Quote:
Originally Posted by sll914
Thank you!

Yes the wing is already experiencing transonic conditions. We even have already had locally SUPERSONIC flow over the upper wing surface. Dr. Drela provided some plots a few years ago showing local flows around m=1.2 when freestream velocity was m=0.65. As a result, the wing on the Transonic DP was specifically tailored to reduce these local velocities and delay the formation of lambda shock waves that cause a huge increase in drag.
That's a great peek into the study and aerodynamic principles of this new frontier. Who would ever have thought that we'd be facing transonic and local supersonic flow for model aircraft. I sure know that I didn't at any time through my whole modeling life since the mid 1960's up to just now.

I've sent off a link to the YT video to some friends that have taken a shot at me in the past over playing with "toy airplanes". It was all in good fun mind you. But seeing and hearing the results in the video should make a few jaws drop...
Jun 14, 2018, 06:55 AM
Mark LSF # 3792
Bruce in a presentation last year he stated that a G meter was maxed out at 120 G, all it could read, in a run prior to the new record run!

BTD10: The 835kph Sailplane and Dynamic Soaring (56 min 0 sec)
Jun 14, 2018, 08:54 AM
Fly Low - Hit Hard
Red Flyer's Avatar
Mind = Blown

WOW @@@@@!!!!!
Jun 14, 2018, 09:23 AM
Happy Flying
mdtang's Avatar
Had no Idea that this type of speed was even possible with no motor. UNREAL. Congrats for all of your effort and skill!


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