Turbine 701

[Planechaser]

Does anyone know anything more about the 701 on youtube powered by a Garrett JFS 100-13A turobshaft engine.

 

That puts the E back in Experimental, or perhaps the mental!!

 

Don't know the benifits over a conventional engine but what a sound!

 

 

[facthunter]

Never been fussed with the sound. Most noise coming from a turboprop comes from the prop. and it almost HAS to be variable pitch.unless in a crude version.

 

Benefits over a conventional engine?

 

Real ones are much more reliable, and lighter for the power developed.. Uses cheaper ,less flammable fuel.

 

Downside. Usually much more expensive to make. Uses a lot more fuel especially at low level..reduction drive is critical as the engine is very high revving especially in the smaller versions. can get hot at the turbine when starting.. Nev

 

 

[Guest Andys@coffs]

short haul RPT's often have to motor the turbine (run up the turbine with the ignitors off) prior to start to get the residual inside engine heat down low enough that they wont have a hot start (turbine temps peak during start and then cool down, the trick is to ensure the peak is under the allowable maximum)

 

With an APU runnning, motoring the main engines is very feasible, yet for a smaller aircraft on battery, I wonder if thats a possibility or needed.....

 

Mind you, when I was in the RAAF the power/air carts used for ground power for the F111's were turbine driven, called the dash60, I seem to recall the turbines weres Garretts, and they were generally treated very badly by ground crew, every start was potentially a hot start, but they just kept on keeping on..... mind you some of them during start had you wondering if staying by its side as it wound up was a sensible thing to do as they huffed, farted and jumped around.....self preservation often suggested that some distance between you and it might have been a sensible thing to do....

 

 

[.Evan.]

I've always wondered what the advantages/disadvantages are for small turbines in light aircraft would be. Cheers Nev.

 

 

[facthunter]

The smaller ones are not much more than a turbocharger, with the outlet and inlet pipe connected with a burner in between. Obviously if you take power off it the balance of the design will not be absolutely correct but all things are a compromise so if you are trying it, you are not venturing into totally unknown territory. Your reduction gearing will have to be from something like an automatic transmission as you will find sun and planetary the strongest for weight.

 

Have some way of reading the temp of the turbine. It can be downstream of it, ( it will be a lower reading in that case). There will be a temp above which you are going to melt the turbine so stay about 100 degrees below that. . The centrifugal compressor is more stable than axial flow and you could not afford one of them anyhow. You have to design a burner can or two so it won't burn holes in the side. It will burn a lot of fuel but you can get an absurdly large amount of power from a small and light unit. which doesn't vibrate, or have things that want to exit the sides. Nev

 

 

[Planechaser]

Uses cheaper ,less flammable fuel.Last I checked Kero was $1.75 by the drum. I guess Jet A1 would be a bit cheaper because it isn't as clean, but would it be cheaper that PULP?

 

Just another downside by the looks..... oh well.

 

The batmobile is on the backburner again.

[facthunter]

Avtur has always been much cheaper than Avgas. I don't have current prices, but can't see what would have changed there except to further disadvantage avgas where the supply is getting more difficult, because of lower volumes. Kerosene is an outrageous price, but you don't need it Nev

 

 

[rocket1172]

You can't beat the sound....the smell.....and the will and desire to be able to do it in the first place. I would love to put one in my Sav. Some things in life have to be done only because we can....they don't have to be truly feasible and logical. From what I have seen in the video, a constant speed prop (and a bloody good one!!) would have to be used to control that approach speed....

 

 

[jetboy]

The 701s are purpose made with wet wings etc. specifically for the requirements of the JFS100 and I think from reading the small amount of technical info he has a good supply of engines and the expertise to keep them running.

 

That said the JFS100 is only 90 shp peak and supposed to run in naked form for max. 5 minutes.

 

Here is an informative article on a KR2 install, be interested to know if its still flying in Australia?

 

http://www.n56ml.com/strent.html

 

fuel flow is likely 45 L/hr in cruise wheres the same performance without satisfying noise can be had with piston engines for 15 L/hr. To use the JFS100 in my 701 I need a serious increase in fuel - 2x 60 litre drop tanks ?

 

and more for background info, my experiments are logged here

 

 

 

Ralph

 

 

[eightyknots]

Here's the you-tube video for the 701: