Last weekend I strapped in a handheld GPS into my Kingcat and clocked max speed at 222mph with the Wren XL 200 full bore coming out of a split S.
Is this about as fast a Kingcat will go ? I have the standard Kingcat no mods except for a 40oz smoke tank and pump, powerbox and powerbox batteries.
Somehow my Bobcat with a 18lbs feels a lot faster havent tried with a GPS yet.
Xantos

Your Bobcat probably is faster.[X(]

Go higher?

We clocked one on the radar gun at 247mph
powered by an AMT Netherlands Pegasus HP

Dude, you need to strap that gps on your BC...im strapping a gps on my KC this weekend. Lets see how fast mine goes with a p120.

My friend Christian has the Weatronic GPS receiver in his Simjet Nexus-equipped Kingcat.
At the Arvika-meet in Sweden he logged 255,4 mph on a flyby after coming out of a dive.

Video here: www.av-art.no/filer/modellfly/411.wmv

Filmed by Cato Horten.

Tor

How accurate those figures are considering the accuracy of a GPS receiver ?
Wouldn't be a radar gun way more accurate ?
I think a GPS is just good enough to get a rough estimate of position, altitude and speed. No more.
It could be interesting to test them side by side anyway.

It may go much faster.. the speed of the airplane not depends only on what engine you straped on it, but also in how much time you allow it accelerate at full throttle, not loosing it´s kinetic energy on turns.

Also flying at a club well over sea level makes noticeable differences..

However I don´t recommend you try to find it unless you have plenty on confidence on your general setup, and a spare jet model!



Enrique

I'm not quite sure about the Weatronic GPS, but the one I have in my car has been tested
against a radar gun over a distance of 400 meters, and the difference was approx 1-2 km/h.
When I drive without a lot of traffic (like today when I went to Sweden for my new GBooster),
the ETA is calculated very exact.
Of course a radar gun (or laser) is even more exact, but we are talking decimals. Even the first
handheld Garmin GPS that I had in my boat was exact down to approx 2-3 knots.
I'm sure Christian's Kingcat would be able to go even faster in winter and after a longer dive/acceleration.

Tor

GPS max speed readings can get funky if there are vertical maneuvers during the flight. I've had a very quick prop job show 260 mph on a hand held GPS, which was clearly in error.

The GPS is good for referencing many passes, but as Bob said, they can definitely give you errors. The GPS is my car was clearly wrong when I accelerated rapidly and it showed a max speed of 124 mph. Although the Magnum will do 124, it didn't during that specific driving experience and generally my GPS is very accurate as some have already stated. This was just accelerating quickly in a car, I'm sure some of the accelrations of our jets will give an even greater disparity of numbers on occassion.

I have some experience with the Eagle Tree GPS, but can only use it fro reference and would not emphatically put my whole trust in it 100% of the time.

My .02 from experience.


George

You Europeans must be getting a different version KingCat....the ones Uncle Bob sells in the states only go 200MPH

Richard

The Canadian version (like the european) that I have did 207mph at about 3/4 throttle with a PST1300R on radar at Princeton jets spring. I did about 5 full throttle passes but we weren't able to record them, it's not a lot faster at full power, I would guess maybe 225 to 230.

At Heart of Ohio this year they had a radar gun and on a down wind pass (maybe 5mph tailwind) they recorded several passes and the highest one was 199 & 30/10ths. Gotta keep it legal. Give or take a few percent error I figure the Kingcat with a little help can do 200 with a P120.

I've HEARD of a guy with a P-180/ Kingcat that went 255MPH with Jetcat GPS and airspeed indicator onboard.

Ooops...double post.

I doubt the KC with a PST 1300 will see over 200mph.
That was precisely the same set up I had on the KC till I swapped the turbine with the 35lbs Wren XL.
I love my PSTs but for the KC the Wren XL @35lbs thrust and installed weight of 1.8kg is a combination you cant beat.
Xantos

I tend to agree with the above comments about the GPS only being relied upon for position, and velocity as a maybe. I tested the accuracy of it while driving around on the street, and came to the conclusion that its not a realistic comparison... There's far less abrupt movement, the antennae is always in the same orientation, the velocities are lower, and the system tends to operate on the same plane at all times. The readings and 3D plots looked far different than that of the aircraft tests...

I run the Eagle tree unit with both GPS and Airspeed, where I've seen some readings appear to be realistic while others are totally out to lunch. The only way to verify speed through a GPS reading is with direct comparison to airspeed, keeping in mind they are not exactly the same measurement and noting the wind conditions while the readings were taken...

I hope someone here gives some accurate speed data on the new KingCat with a Titan, since I've been contracted to build one for a new jet guy up here... I'd like to know what Its capable of before I go to maiden it in the spring time!

Kelly

I 'm sure it all has to do w/ the sample rate of the particular unit involved as opposed to the GPS as a concept. I've tested 3 seperate units and found them all to be quite accurate.

At a small jet rally this past summer I pointed the radar gun at a couple of different airplanes.
Kingcat with Titan SE on the level was about 215mph. After a moderate downhill run about 255mph.
Bobcat with P120 was about 265 in a shallow dive.
Altitude was just short of 3000 feet... Temp about 75 degrees.
Obviously these jets are capable of speeds well in excess of the legal limit and I'm sure many already know this.
Keep this hobby safe so we can all continue to enjoy it.