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

Turbines Vs Props

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Old 03-10-2003, 05:18 AM
  #1  
FlooredCOBRA
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Default Turbines Vs Props

I was curious to know what kind of speeds those turbines reach compared to our speed prop planes. Are they a whole lot faster or about the same or does it depend on the plane and all?

I am sure some are really fast but wanted to get an idea what the normal for speed wise they are going. Was wondering if it is a lot faster or about the same.

I know its kinda of like speed prop planes it depends on the aircraft and i guess turbine size. Same with us on what plane type and what engine. But does anyone know a round about speed that these turbines reach?

A while back I was flying my dust and a guy there said it looked faster than some turbines he seen fly. I know that there are some that are supposed to really haul like i seen a few videos on here with some in it and they do haul. But was curious as to whats a normal speed for them.

I know most of us are running 150 mph to 190 mph+ as a normal just curious as to what these guys do.

I guess what got me wondering I was looking at a trainer type turbine jet called the Topcat.
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Old 03-10-2003, 01:50 PM
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Default Turbines Vs Props

Turbines will take you into a new realm. A place where your eyesight becomes very improtant. Most turbine pilots fly at 1/2 throttle or less for most of their flight and still maintain average flight speeds in the 150+ mph range. Throttle control becomes manditory with a turbine. Many people think turbines aren't very fast because most turbine pilots have the good sense not to push the limit. They fly at sensible speeds.

I can tell you my Dust will never keep up with my Roo (RAM 750). While it may appear to be as fast because the dust is much smaller, this is just an optical illusion.

Mark M.
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Old 03-10-2003, 08:50 PM
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Default Turbines Vs Props

okay i did not know that about turbines flying with throttle left over. I always thought they went WOT. I seen a few videos with some turbines flying but it is very hard to get an idea on what they are like compared to seeing in real life i guess.

I was looking at that TOPCAT last night it says its a trainer jet. I was curious on about how it would run. Also what all is involved in starting and running a turbine. From the videos it looks like you need some gauges and some other equipment.

How do you go about learning about turbines besides reading directions. Do they have like classes or some kind of training on them on does and donts? I know there must be more to it than just cranking one up.
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Old 03-11-2003, 01:40 AM
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Default roo vs. whiplash

I feel more secure with the whiplash going 200 than the roo going 200. My roo has no gear doors and there have been some reports of the fue coming apart due to air pressure buildup inside the fuse. I built it according to specs but it comes prejoined from the factory. The whiplash seems much stronger to me and doesnt have the large wheel openings to allow this to happen.
Thrust is not an issue with the turbine. There is another thread that addresses the efficiencies of props, fans, and turbines at high speeds. Has to do with how fast they can move air. i am no expert but will try to find the link that explained it.
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Old 03-11-2003, 01:54 AM
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Default Turbines Vs Props

yeah that would be great.

I am curious about these turbines and how they work. I think the only thing that I would be scared about them is maybe bouncing on a lading while that thing is spinning so fast. I would be afraid that it would get out of balance on me.

How durable are they? Also i read on some adds about the lbs they can push. Is that on ground thrust or in air, does it get more thrust once it is moving?
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Old 03-11-2003, 03:56 AM
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Default cant find the link

Basicall if i remember correctly all these engines lose efficency at higher speeds. As the limit of the air speed flowing out of the back of the setup is reached you lose the thrust. For a prop its 200mph, fan 250 mph, turbine 600mph. This is for size of engines we use not the big ones and are just approx. values. I am not an aeronautical eng. This is what i recall from this forum. Hopefully someone will explain it to us. Im just answering because nobody else is. I will look for the link tomorrow.
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Old 03-11-2003, 03:56 AM
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Default Turbines Vs Props

Here is my Topcat caught in a very slow flyby. I have a Jetcat P80 on it. To start it, I just put fuel in the fuel tank, top off the onboard Powermax container. Then stand back and flip a switch on the Transmitter and it starts itself. Not all are this way, but the jetcats are known for reliability. My topcat is not super fast to me, Ill put up a video of a full throttle fly by if you like, power to weight is about 1:1.

What makes prop jobs so much less stressful, is your not going to loose $5000+ on a crash.
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Old 03-11-2003, 04:20 AM
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Default Turbines Vs Props

Originally posted by FlooredCOBRA
yeah that would be great.

I am curious about these turbines and how they work. I think the only thing that I would be scared about them is maybe bouncing on a lading while that thing is spinning so fast. I would be afraid that it would get out of balance on me.

How durable are they? Also i read on some adds about the lbs they can push. Is that on ground thrust or in air, does it get more thrust once it is moving?
They are pretty durable, to a point of course. My Topcat in that picture, I stalled it coming in on a landing and pancaked it onto the runway from 20' or so flat. Engine ran the whole time, and did the shut down after it quit sliding to a stop. I have ran the engine since and there appears to be no problems. Its going into my BVM F-86 sabre now

Little bounces seems to not affect them. And everyone has done it
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Old 03-11-2003, 04:53 AM
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Default Turbines Vs Props

yeah would love to see some video.!

Nice pic by the way!
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Old 03-11-2003, 05:00 AM
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Default Turbines Vs Props

OK, will get some up tomorrow for ya!

Here, I snapped this pic on a cold day firing up the engine
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Old 03-11-2003, 05:09 AM
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Default Turbines Vs Props

great thanks! awesome pic!

So what is it like flying a turbine compared to a fan? Is it about the same or are there any differences?

I would love to have one myself just to hear it running.. I think I could just site there and play with sound of it all day long.

Have you put a radar on that Topcat yet? Curious on the difference in speeds compared to speed prop planes.
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Old 03-11-2003, 05:16 AM
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Default Turbines Vs Props

Its a little more stress, but its alot of fun, the sound is amazing and the speed is easy to come by. There fast. No radar, but Im sure its not doing 200, maybe close, I dont know????

They are heavy, this plane weighs 17.5lbs, and does not have a huge wing. So, its gotta move a little fast to stay up. Was a good plane! They are MUCH easier to run and maintain, Id take a turbine over a D/F anyday, its the price that sucks.

Here it is.
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Old 03-11-2003, 01:08 PM
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Default Turbines Vs Props

Most of the information you are requesting can be found by searching the Jet forum. Here is a link to the Jet Pilots Org.. All of the AMA documents on turbines can be found there. If you want to know how a modern turbine works, check out the manufacturors web sites and download the manuals. The manuals are very complete and get into more detail than most need or want to know.

Starting procedures range from manually controlling starting air & fuels going to full automatic where you just flip a switch. More important is fire safety equipment and the experience to know when to use it. In the AMA documents there is a list of Turbine CD's. I would contact one of those guys in your area. I'm sure they will direct you to a field where you can watch the process and get a feel for what you might want to do.

Flying a turbine vs a dusted fan. There are a few differences. Turbines have throttle lag (although this is getting to be less of an issue with the newer versions). This means when you hit the throttle it takes time to respond. For this reason you must always be ahead of your plane. The same occurs when you cut the throttle. At idle turbines have higher rresidual thrust. Because of this most planes need help slowing down to land. Flaps and speed brakes are very common on turbine planes. Wheel brakes are almost manditory as well.

So, even an entry level turbine increases the pilots work load with flaps, air brakes, wheel brakes, throttle lag, heavier wing loading, higher landing speeds, shorter flight times, setting failsafe, less room for error and the constant need to be able to shut the engine down if you know you are in trouble. This list can be shortened be planes like the Facet, but shortening this list will most likely result in buying a plane that isn't as fast. Call SKS and buy the Florida jets tape from 2002. That tape has some of the most powerful turbine planes all the way down to the slowest flight you can imagine.

Good luck in your final choice,

Mark M.
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Old 03-11-2003, 07:06 PM
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Default Turbines Vs Props

Here is the vid.
3.9mb

There is takeoff, slow pass, two high speed passes, then landing.

Topcat
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Old 03-11-2003, 07:51 PM
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Default Turbines Vs Props

If you want to see the insides of a turbine, I have some pictures on my site. I bought a Simjet Sonic 120 which you assemble yourself.

press the menu on the right "Sonic 120 AES"

http://bornholm.adsl.dk/modelfly/hp/start.php

SJ
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Old 03-12-2003, 12:17 AM
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Default Turbines Vs Props

nice video! man that thing sounds awesome
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Old 03-13-2003, 01:25 AM
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Default Turbine speeds, etc.

Floored,

I'm not sure anyone really knows how fast turbine powered models can go. Unlike prop planes which accelerate to a certain speed and then hit a "drag wall" turbines just keep accelerating.

HotSpots like mine in my avatar have been clocked at 240 plus on radar but keep in mind we fly in confined spaces. Given five or ten miles to accelerate I wouldn't doubt a HotSpot or Bandit could hit close to 300 with ease.

Most guys routinely fly their turbine jets at around 1/2 throttle. When I fly my HotSpot I take off at full throttle and immediately throttle back on downwind. I go full throttle for one high speed pass that ends in a giant loop and another that goes into a series of vertical rolls. I once left the jet in full throttle after a high-speed pass and brought it around for another one. The speed was absolutely ridiculous, downright scary. I honestly don't know how fast it was going but it was fast enough to make me suck that throttle stick to idle right now.

To get back to your original question I would have to say that jets are, in my opinion, certainly capable of much higher speeds than the Whiplash, Diamond Dust or Magnum. I was at Florida Jets two years ago and witnessed a Bandit make a pass at 260 mph, confirmed by a GPS stuffed into it before the flight. You simply can't believe how fast 260 is with a little model airplane. It literally goes by in a flash.

Normally; however, model jets are not flown anywhere near their top speed capability.
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Old 03-13-2003, 02:47 AM
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Default Turbines Vs Props

hey john that flaming told me that the turbine had a rich start fuel built up
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Old 03-13-2003, 03:48 AM
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Default Turbines Vs Props

260 now that is hauling! I guess it would come down to who can has the best eye site also being they go so dern fast. One second its over there and next its down there and then just trying to see it and turn before its out of site.

Thats awesome! I always thought they flew WOT full time. I never knew that they had to stay off and on throttle like that. Thats totally a different ballgame!

All I can say is I want one!
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Old 03-13-2003, 03:48 AM
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Default Turbines Vs Props

It was very cold too.

Doesnt do it anymore.
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Old 03-23-2003, 06:42 AM
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Default Turbines Vs Props

Whiplash #2 will see the sky today. This one will havea Jett FIRE .50 8.8x9 APC pylon prop. I still have to finish break in and final tune of the pipe. Speeds 125 durring breakin 175 is expected when final tuning is complete.

After waivers are completed A Kangaroo and RAM 750 will be my next plane. RAM cruise control will hold Vne at 200MPH.

Do to its size the whiplash will look about 20% faster than it is.

But NOTHING beats the sound of a turbine.
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Old 03-23-2003, 06:58 AM
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Default Turbines Vs Props

I am sure it wont be long before someone straps a turbine on a delta. And I mean really make one work not just set one on top and take a picture.

Now that would be a pure rush flying something like that.
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Old 03-23-2003, 06:59 AM
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Default Turbines Vs Props

Been done, I think there is an enfocer on ebay with a turbine...Seen it somewhere.
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Old 03-23-2003, 07:00 AM
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Default Turbines Vs Props

well there we have it!......

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Old 03-23-2003, 07:02 AM
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Default Turbines Vs Props

Also, do a search in the jets forum, mec I think has a tiny delta thing with a turbine on it, has been radar'd too, and was FAST!!
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