Scale ME-262

[Erik Snyman]

VHHJR, I love what you are doing. Getting real live data out there. Can I start drawing some plans for my scale Boeing Skyfox fighter, do you think? The fans will go where the turbines on the photo is.....
Erik in Oz.

 

[Erik Snyman]

Hello folks

I was wondering, in line with the work vhhjr posted above, would multiple fans per hub (say 2 rows), with the foremost fan blades with lower pitch, second row with higher blade pitch, not work? Sort of like a fan compressor, the first row accelerate the air stream, for the second row to get a faster airstream intake? Just wondering...

Erik in Oz.

 

[pictsidhe]

If designed correctly, yes. But unless you have a huge power loading, a properly designed single row will be just fine as well as being a lot simpler and lighter.

 

[vhhjr]

The blades are the hardest part of making a ducted fan. With compressor blades the twist isn't quite right and the pitch is wrong if you mount them as mounted in the jet engine. But, ya gotta start somewhere and they beat bending them up from flat stock. I suspect I could optimize the blades if I had access to an entire set of compressor blades as each row has different pitch and twist.

I did make the blade angles adjustable in the 11 inch fan and it made a big difference.

The first hub I made for the 17 inch fan mounts them in the same orientation as in the jet engine. The next task is to make an adjustable blade hub.

An alternative to a multiple row arrangement is a two rotor contra-rotating fan with the advantage of taking the swirl out of the exhaust stream. If you use a same direction, multiple rotor fan you have to have stators in between the rotating rows and the swirl is still there requiring an exit stator row.

Nothing is simple!

 

[Erik Snyman]

The blades are the hardest part of making a ducted fan. With compressor blades the twist isn't quite right and the pitch is wrong if you mount them as mounted in the jet engine. But, ya gotta start somewhere and they beat bending them up from flat stock. I suspect I could optimize the blades if I had access to an entire set of compressor blades as each row has different pitch and twist.

I did make the blade angles adjustable in the 11 inch fan and it made a big difference.

The first hub I made for the 17 inch fan mounts them in the same orientation as in the jet engine. The next task is to make an adjustable blade hub.

An alternative to a multiple row arrangement is a two rotor contra-rotating fan with the advantage of taking the swirl out of the exhaust stream. If you use a same direction, multiple rotor fan you have to have stators in between the rotating rows and the swirl is still there requiring an exit stator row.

Nothing is simple!

That`s so true. If it were all easy, we would all be doing it!! Anyway, thanks for your time, effort and dedication. I, for one, am looking forward to your ultimate success. If the Russians can figure it out, so can you. ( No malice intended, Malish!)
Erik in Oz.

 

[Speedboat100]

Put the Swastika on backwards and get over it!

We finns have no problem with our swastika. Germans seems to be in deeper regret on that subject.

 

[Speedboat100]

Kikka was pretty modest in speed: https://en.wikipedia.org/wiki/Nakajima_Kikka

 

[vhhjr]

An update on the fan projects.

Both the 11" and the 17" fans have been converted to adjustable blade pitch and some testing done with the new 35 HP 2Si engine in place. The data was a bit disappointing and proved the ex-turbine blades were not ideal for ducted fan use. The maximum thrust I got from the 17" fan was ~40 lbs and from the 11" fan about 25 lbs. The maximum thrust/hp was around 3.0 with most tests showing around 2.0 lb/HP.

We are now in the process of designing new blades that will be made from 3d printed molds using carbon fiber/epoxy. These blades will also be pitch adjustable. I'm also re-vamping the data acquisition system, hopefully for better data from future tests.

I have attached a photo of truing up the fan OD with a grinder. Titanium is fun to grind.

 

[vhhjr]

Update: Not much happening with the giant ducted fan project. Seems we have gotten involved with a NASA funded project looking at ducted fans on STOL aircraft. Should be done by mid-winter and will be looking for the next project. Happened to notice my set of Jet Hawk plans in the shop bookcase. Hmmmm!! Move the fuel from behind the pilot to the wings and make it a two place. It's also very short coupled. We know a lot more about designing ducted fans than the designer did 30 years ago.

Vince Homer

 

[Jay Kempf]

nn

 

[Yellowhammer]

Scaled warbirds are difficult projects, jets more so. the engines you propose are over $60k each and burn about 40 gal/ hr each for TO thrust. There is a higher thrust version that you would probably want for more performance and higher cost. How much time and money do you have. Buy an L-29, full size.

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The engines in the sub sonix do not cost 60K each.

 

[Yellowhammer]

I would like to build a scaled down A-4 using one of the TJ engines. My dream plane for sure as far as jets are concerned. The P-38 is my prop driven choice.

The 262 would be a very nice project and I hope to see it come to fruition.

 

[Yellowhammer]

VHHJR, I love what you are doing. Getting real live data out there. Can I start drawing some plans for my scale Boeing Skyfox fighter, do you think? The fans will go where the turbines on the photo is.....
Erik in Oz.

I have never seen this aircraft before and I like the hell out of it. I bet it is a very fun plane to fly.
Kind of like a civilian A-10 minus the bus sized gun.

 

[Yellowhammer]

An update on the fan projects.

Both the 11" and the 17" fans have been converted to adjustable blade pitch and some testing done with the new 35 HP 2Si engine in place. The data was a bit disappointing and proved the ex-turbine blades were not ideal for ducted fan use. The maximum thrust I got from the 17" fan was ~40 lbs and from the 11" fan about 25 lbs. The maximum thrust/hp was around 3.0 with most tests showing around 2.0 lb/HP.

We are now in the process of designing new blades that will be made from 3d printed molds using carbon fiber/epoxy. These blades will also be pitch adjustable. I'm also re-vamping the data acquisition system, hopefully for better data from future tests.

I have attached a photo of truing up the fan OD with a grinder. Titanium is fun to grind.

Sir, I am extremely interested in your project. Do you have any more pictures and information available I could study please sir

Sincerely and Respectfully,
Yellowhammer

 

[Yellowhammer]

We finns have no problem with our swastika. Germans seems to be in deeper regret on that subject.

I agree. The German shouldn't be. It is history and we must never forget. Plus the Swastika is a religious symbol from Tibet. Used for centuries!

 

[cluttonfred]

I absolutely disagree. The Finnish use of the swastika predated the Nazi party and had nothing to do with fascism, but even they decided to change their national aircraft markings because of what the swastika had come to represent. The Nazi swastika represents a regime that committed some of the worst atrocities of modern history and the Germans are absolutely right to relegate to the scrap heap of history.

 

[pictsidhe]

If I ever build a Nazi airplane, it will probably get reversed swastikas.

 

[cluttonfred]

I agree that I don’t want to get into politics here, I was commenting only on the use or omission of the swastika on a replica of a WWII aircraft.

 

[Riggerrob]

I have never seen this aircraft before and I like the hell out of it. I bet it is a very fun plane to fly.
Kind of like a civilian A-10 minus the bus sized gun.

Skyfox was an attempt at re-engining and up dating all the Lockheed T-33 jet trainers. Boeing was hoping to convert hundreds flown by Second World and Third World air forces. They only converted the one prototype.

As a young RCAF technician, I worked on Canadair-built T-33s with Rolls-Royce Nene 10 engines. They were first-generation, centrifugal engines that were extremely reliable, but consumed a fair amount of jet fuel. They were so reliable that they continued in service past 2000.

 

[cblink.007]

If you are serious about this, you need a set of A.L. Bentley drawings. He has Me262 sets. I am using a set to design my Hurricane. I can confirm that they also look great on the wall! At 1:24 real scale, they are 1:16 at my 2/3 scale. More detailed drawings are useless unless you are building a full size replica. With a scale and much lighter aircraft, you will need to drastically alter the structure, so you can look forward to engineering the stresses yourself.

A.L. Bentley drawings. A trove of great material. I got the entire set of Ho-229 drawings he did; ended up copying some of them and putting them up in my workshop!