alasdair

Just flown my new jet powered plane fitted with floats, and it went great .
It is an own design Jet Trainer model, span 80" weight 13 lb on wheels, 15 lb on floats.
Powered by a Wren 54 mk3 rated at 14 lb thrust.
Floats are home made, hot wire cut veneered foam, 51.5" long.

I was a bit worried that the engine would suck up some water but there was no problem. It taxied around fine on the single water rudder, take off was fairly rapid and it is still fast and agile in the air. Approach and touchdown using full flap no problem.

I have heard of a few other jet seaplanes. Anyone care to post photos?

Alasdair

Deadeye

Cool! I like the low slung look of the floats. I guess you don't need to worry about prop clearance!

Lamoilleriver

WOW, cool beans.[sm=thumbup.gif][sm=thumbup.gif][sm=thumbup.gif] Now on the list of things I like to try list. Great job. Video????????

alasdair

Thanks guys.
Another 6 flights today, but no more photos or video. Maybe next time.
Keeping the fuselage low seemed the obvious way, as there is no need for prop clearance as you say. It is less likely to tip over.
CG had to go forward 1/2 to 3/4 inch when converting to floats, so maybe I'll move the floats 3/4" further forward. Otherwise seems perfect. Today the water varied from glassy calm to rippled, but no problem.
Alasdair

mscic-RCU

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Coooooooool!

Wayne22

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A fellow in our club has done a turbine powered Northstar.... unfortunately, I can't find any pictures of it.....

phillfix

I have a 150% North star waiting in the to do bin for turbination so many plans so little time .

alasdair

A friend of mine called John Campbell flew a jet powered 150% Northstar a couple of years ago. He has now decommisioned it unfortunately. Here are a couple of shots at Loch Insh.
I think the engine was a TJT 3000.

Wayne22

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Someone posted a pic in the twin and multi forum - so I borrowed it!!



**** photo by RZAPP ************************************************** *****

alasdair

Hi, I wonder if that is a smoke system?
Any photos of the rear end to show the engine and how it breathes?
And how big is it? tell me more please
Alasdair

Planker07

That is smoke. The turbine is mounted on top of the back end of the fuse and there is a small deflector incase water spray comes over the front of the aircraft. He has his speed brake deployed so you are unable to view the turbine. One awesome flying aircraft.

JohnBuckner

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Your project is a wonderful achevement alasdair congratulations. Its difficult to tell from the photos but where is your intake and has water ingestion presented any problems?

John

Goinstraightup

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Very nice!! I was wondering about the intake too

alasdair

It has had 40 flights already, and never seemed to need intakes.
Attached photos show that the engine is open on the underside, so the air can get in the bottom and round to the front of the engine. It just sucks air from wherever it can get it. I have yet to fly it from rough water, but I have flown it when the water is glassy smooth, rippled, and a little choppy and not had a problem with water splashing in.

However, everybody who sees the model asks "where are the intakes?" so it is in the workshop now having intakes fitted. I intend to test the model with the intakes open, and with them blocked, to see if it actually makes any difference.

Wayne22

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It looks like it is getting a little toasty under the aft fuselage...do you have any heat protection back there ?

alasdair

Oh Yes!
From the engine back the underside is covered with ceramic blanket, said to protect the structure from up to 1000 degrees C. It is necessary, as you can see. The film on the bottom tip of the rudder was burned on one occasion (I think when the hot exhaust was squeezed between the tail and the runway when rotating for take off). The bottom 1/2" is now covered with stick on aluminium.
The tailplane is film covered and the only time I ever had a problem was when I tried a silly experiment with engine parameters, resulting in a tongue of flame and a little bit of melted film.

alasdair

I managed to get some video of one of the flights at Lochearnhead last month. Posted on youtube, here's a link (hope this works)
http://www.youtube.com/watch?v=VWtlSaf9uSw
Alasdair
P.S. it works!!

Lamoilleriver

Sweet airplane, was fun to watch the video. Great job.[sm=thumbup.gif][sm=thumbup.gif][sm=thumbup.gif]

Wayne22

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alasdair How much does it weigh with the floats? and how long are your floats? I have a green powered Baby boomer, and a spare set of 42" floats sitting downstairs, and you got me thinking...............................

alasdair

Wayne22,
Without fuel, JayTee weighs 13 lb with wheels, or 15 lb with floats. The floats are 51.5" long, 4.3" wide and at the step they are 3.75" deep. They have a flat bottom, plus spray strips down both edges back to the step.
I considered floats on my Baby B but couldn't think of a neat way of fitting them.
Alasdair

Wayne22

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I just remeasured them...they are actually 48" long and 7" wide... a bit short if you go by the 75% rule. But, I may give it a try....
I have a general idea how I would mount them, but have not actually tried to line everything up yet, so there may very well be some head scratching involved.......

Have you seen this video?
http://ca.youtube.com/watch?v=k6c-LweM-VM

alasdair

Wayne22,
That's great, many thanks for the link. I had never heard of that one.
It looks as though it flies well, but could maybe do with more tail clearance to rotate on take off.
Alasdair

Wayne22

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I wonder how long those rudder servos will work underwater???

alasdair

Good point. I wonder if he repositioned them?

By the way, I had another 5 flights today. Beautiful weather, though a bit cold at +5 Celsius.
On one of them I turned the top revs of the Wren 54 down from the usual 160000 to 136000 to simulate the power of a Wren 44Gold, about 10 lb thrust. JayTee still performed great, took off easily climbed out strongly and aerobatted just fine. The loops were no longer gigantic though.
After that, having proved my point, I turned the wick back up to max.

Another by the way, a couple of weeks ago I added air intakes on the fuselage sides, with holes to let the air through the sides in to the front of the engine. And I put metal mesh to stop anything lumpy getting through.
Worked just fine on the first take off.
Second take off came to a hissing stop with clouds of white smoke when the engine flamed out - I suspect water getting into the intakes and dousing the fire in the engine.
Third T/O no problem, but after that I blocked up the intakes and the engine is none the worse.

Yet another by the way, for today I added another piece of wood under the front of the engine to further restrict the chance of water getting to the engine intake. The air still gets in and the engine is none the worse. I didn't bother with photos but I'll get some another time.
Alasdair

Wayne22

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I guess with that low slung profile, the engine is not that far above the water..... I figure that The BB with its over-the-wing (albeit tiny) air intakes, should be more spray proof... I won't be doing anything til later on in the winter ...My son has an f-22 on my building table right now.....