A freind of mine did this today playing around, I found it to be interesting. He clocked his heli and a plane.

Link to stats.

Well if that plane will go 142 mph you are going faster than the pylon racers at the Nats, who have more powerful engines and lighter planes. We had a policeman where I fly come over many times and check the plane speeds on Radar, a Hot's with a .91 in a dive, the best we ever recorded was 88 mph, a plane that looks similar to the one in the pic's. If you divided by two that would be closer to the speed. Chris

I hate to bust on anybody, but have to aggree with airdodger. I flew planks for many years, and the whole "Hots" line were my planes of choice. I have a "Hots 2", which has a 42 inch wingspan. I have a "Jett 50" with a tuned pipe on it. (among the hottest motors on planet earth) That plane will do full bore snap rolls that will make the most experianced pilots gasp for breath! A buddy who coaches baseball came to the field one day with a radar gun. The plane was clocked at around 120 coming out of a dive. In not saying the above mentioned plane is definately not doing 145, but unless a plank has a very thin airfoil, its just not likely.
Harris,

Hooligan, at large

Well I do not believe the GPS unit is lying. I have used this GPS in my pickup, and it tracks to the speed of the speedometer.
When you were checking your pylon racer speed, were you going for consistent level flight, or were you trying to see how fast it will go. I am sure you were going for consistent level flight.
Well I was going for how fast I could get it to go. And since this airplane only weighs about 4 + pounds, it moves right along.
But the Heli is what surprised me, people who don’t fly helis, think they only hover, well I guess they move right along. I am building a Fury Extreme with a YS .91, and I will speed test it when I have it finished, and broke in.

Rader, schmadar

Police radar guns are designed to measure the speed of big metal objects like cars, not tiny little things made of plastic and/or wood. The returned radar echo from something as small and as non-reflective as a model plane is going to be feeble and unreliable. I wouldn't trust any speed measurements made on models using a standard police radar gun.

GPS doesn't lie!

If you don’t trust GPS (why not?), the next best thing would be to time a flight over a measured distance.

GPS’s don’t lie.
But they can be fooled.
If you did a long dive to reach top speed the antenna was pointed straight down.
When this happens the GPS may lose contact with the satellites. When the GPS loses contact with the satellites it assumes that the last known speed and direction remained constant. When the signal is reacquired and processed, the calculations are made from the last assumed position to the current known position. That time and distance is used to calculate your speed.
I once used this to prove to someone that I can run at 32 mph.
Although, sometimes it seems that my Great grandaughter can move that fast.

There are radar guns that have no problem tracking a baseball at 100+mph. A baseball has a lot less metal and mass than a heli.

Jeff Borowski
RAMS Club President
www.ramsrcclub.com

The radar gun that Harris mentioned in his message was not a police radar gun, it was one of the "sport" radar guns used to clock the speed of baseballs, hockey pucks, etc... not big metal objects. I'm not saying that the numbers posted in this message are wrong, just unlikely (as far as the Hots goes) Especially with a 6oz plastic device hanging on the top. I'm not sure about the heli... that's more reasonable.

-Steve

How much error do you think was in it using an educated guess, and how fast do you think normal is. Pylon racers also have many diff classes and regulations they abide by. I have seen RC planes over 200MPH, I owned a Diamond Dust with a Jett40 and believe me it would motivate! It was well over 100MPH and faster than many at NATS. Those speeds are ground speed and not airspeed as well, wind conditions factor in, tail wind?, I think the GPS was pretty close IMHO.

http://records.fai.org/models/current.asp?id=195 This is the current record for helicopters, 144.67 km/h is 89.89 mph. Chris

I fly a 'Vendetta' FAI pylon plane with a Neslon 40 and it looks and feels like its flying 200 miles an hour. But in reality it was clocked at 128.

Tom

Just a simple question, but might sort it all out

Is the scale in MPH or KPH?

Just a thought

Steve

Jasper 7
T-Rex 700N
T-Rex 600N
T-Rex 450Pro

Citizen Number: 00212

Weston Magnum over 200mph

Couple of these at our club and they shift:

http://www.westonuk.co.uk/arflist.html

MagnumR
New! Re-styled to an even sleeker shape, cuts through the air more efficiently.
New laser cut construction adds more strength at no weight penalty. Now covered in metallic yellow Oracover with a carbon effect canopy and highly visible chequered film bottom.

This model is ultra fast (capable of speeds in excess of 200mph) and super stable. With its sleek jet-style appearance the only way to describe the Weston Magnum is simply balisitc! With a lightweight wood and fibreglass fuz, the wing is balsa covered foam with a high speed laminar flow section. Wingspan 875mm, Length 1070mm, Weight 1.75Kg, Radio 4 function, Servos 3 standard,
Engine .40-.50 2 stroke

Is the scale in MPH or KPH?

The display says MH on it.

-Steve

Yes it was in MPH.
Well I have talked to a few people, and there are people with simple stock planes that have been clocked by Radar gun's over 100 MPH. One was a Cloud Dancer, another was a SIG Cobra with a stock .40. Another was a delta wing with a .60 clocked at about 120 MPH at a fun fly.
So I guess it is possible that the GPS is correct.

Well I want to be accurate so I did it again, with the plane, and this time No diving, just straight away, the plane did not do any dives, more than very gradual to land, and only flew about 100 feet or so at the heist,
The level flight speed was 117 MPH. Pictures added to the web site.
Speed Test

I still say the Weston Magnum can blast out at over 200MPH as a number of flyers in the UK will tell you. BTW it looks a lot slicker than the plank you clocked at 140MPH.

Have a look

http://www.westonuk.co.uk/arflist.html

Well OK then, Im convinced!
Harris,

Hooligan, at large

Are there others out there that have tried this?

So the GPS lies?

actually, the gps just may have made a mistake because of it's dependancies on satellite communication.

here's how consumer GPS's work as it pertains to this error:

heli flies this pattern (note timestamps and distance below):

A --------- B ---------- C ----------- D ----------- E
0s ------- 10s ------- 20s -------- 30s -------- 40s
1m ------ 2m -------- 3m --------- 4m --------- 5m

if the GPS remains in contact with the satellites and gets an accurate assesment throughout all 5 points, the max speed is correct.

however, lets say that communication was interupted at point B and the GPS picks up the satellite (and starts measuring again) at point D. it's D=RT profile looks like this:

A --------- B ---------- C ----------- D ----------- E
0s ------- 10s ------- 10s -------- 10s -------- 20s
1m ------ ? ----------- ? ------------ ? ----------- 5m

i've seen my Garmin report my truck doing over 200mph because of this same interuption.

i'd suggest making several runs and take the mean avg. what do you guys think?

Flytech
That is exactly what I tried to say. I just didn’t explain it as well.

Instead of the mean average, I think that the slowest speed would be most correct.
The average of a bunch of inflated speeds will still be a high number.
The only way that the GPS would show a slow speed is if you went from

A-------B-------C--------D--------E
0s-----10s----10s-----10s-----20s
1M----2M-----3M------2M------1M

Where you returned to near the start point before the satellites were reacquired.
I think that this is unlikely with an RC aircraft.

That is why I think that the slowest speed is most likely to have maintained satellite contact.

What cha think?

Jeff Borowski
RAMS Club President
www.ramsrcclub.com