Gordon W

The thread title is a parody on the title of the song of almost the same name by Pete Seeger and the Weavers from wa-a-ay back. I'm hoping you jetsters spot my inference in EDF terms, in that not all EDFs sound like a foamy. The Seeger song is one of my faves from my formative years and I liked this pacy version : http://www.youtube.com/watch?v=MeH-3VFaPak

The foregoing serves to introduce another video of my cool-sounding Stumax-powered Hawk shot yesterday evening by Ron Laden. Thanks Ron! I'd been trying to work out a coordinated aerobatic routine all day, but as soon as I firewalled the throttle for take-off that all went by the board, so I just flew the ship and did any manoeuvre that came into my head on the spur of the moment. The video is actually edited down from a couple of flights we had so is somewhat disconnected in places, not least because I think we both had probs keeping up with the blighter on occasion!

I still need to do some more work on the landings too - the one in the vid is around the 52nd Maybe I should have sat the pilot in the front seat to give him a better view

Not to mention the attempted rolling loop which you might notice at the 2:05 point, which I tried to do for the first time yesterday evening, and got 3/4 the way through it both times before it went to worms

The temp was down in the low 50's so it took a while for the batts to warm up, but when they did ...

The local Air Cadets had been watching some of the flying from where they'd been drilling outside their headquarters, which is about 300m from the main runway as the crow flies. During the second flight their CO came up and asked me if I'd take the model down to them and show them round it. So I taxied it off the runway and round the peri-track and they all stood round whilst I explained about the model and background to the full size Hawk on which it's based. They had been thinking that the model was turbine powered so were pretty impressed that an electric fan could move a model like this so well. They also confirmed that all they could hear was the merest whisper from it in flight, so I guess that the houses which are about another 200m away never heard a thing.

Be aware that in the vid, the shotgun mike I have on the camcorder effectively amplifies the plane's sound while ignoring the ambient noise.

Power this evening, once warmed up, would be around 3.5-3.7kW. Weight is around 15.5lb.

Here's the vid; http://www.rcuvideos.com/video/Stuma...ep-08-23MB-wmv

Gordon

gregg f

My Feedback: (20)

Sweet Gordon![8D]

Meesh

My Feedback: (135)

Tell us the truth Gordon. It's really a Turbine isn't it?

It surely sounds like one! Impressive performance and GREAT sound.

Bob

E.N.T.

My Feedback: (1)

Gordon: Why dont you show us the inside of that plane? I cannot believe that's an electric turbine.

PLEASE show us the inside.

THANKS

Hector

uncljoe

My Feedback: (8)

Looking Great ! Like the sound. BTW how is it done with the flaps ?
Semper Fi
Joe

Vincent

My Feedback: (61)

Nice sounding edf. What size fan is in there??
V..

AndyAndrews

Can you give us the specs? nm saw it attached to the vid. Thanks

Wayne22

My Feedback: (2)

I was going to say "great flight!"......then I saw the landing


Very very impressive machine...sounds unlike any EDF I have ever heard!!

petera38

Hi Gordon,

VERY IMPRESSIVE AND VERY CONVINCING!!

A read about the set-up in r/c jet intl. however seeing and listening was really something else.

Regards from Pete Alstrup,
former Dane now a Swede...

Ron101

My Feedback: (22)

Yep the Stu Max Fan just sounds amazing.

Here is a link to his web site : http://www.stumaxaircraft.com/pages/product.htm

Ron

Gordon W

Hi Guys

Thanks for your kind comments. I have to say that I never expected to have to prove it’s an EDF and the photos below bare all.

The plane is a Fox-Composites Hawk about 58in span and length. I modified it for EDF from the turbine version, making new ducting and setting the EDF unit about 12in further rearwards than the turbine would have gone. The plane weighs between 15lb and 16.5lb depending on the battery pack I put in there (varies from an 11S TP5000 to a 12S TP6600). Power varies between 3.1kW (4.1hp) on the 11S 5000 to 4.2kW (5.6hp) on the 12S 6600. What you saw in the video was around 3.6-3.7kW (4.8hp) on a 12S TP 5000 pack with an auw of about 15.5lb. Wing loading is around 60oz/sq ft.

The SM110-52 fan unit is new to the market, made by Stuart Maxwell in Sydney, Australia, www.stumaxaircraft.com and has a 110mm diameter impeller with a 52mm dia motor tube, giving a fan swept area (FSA) of 74sq cm, 11.6sq in. The fan comes ready assembled with a Neumotor 1915/1Y, and weight is 25oz.

Stu used Computer Fluid Dynamic Analysis (like Jetcat used to design the new compressor on their P120SX) to design the entire fan unit to maximise efficiency whilst minimising the noise footprint.

My fan unit was an early version with carbon shroud. Photo 1 gives an idea of the size, and photo 2 shows the rear view – the unit is a pusher design.

Photo 3 shows the innards, with the cast alloy stator unit which is cnc machined to fit the motor and act as an excellent heatsink.

Photo 4 is the impeller.

Photos 5 & 6 show the current production unit with injection moulded shroud, though the insides are the same.

Photo 7 shows the insides of the Hawk, with a pair of TP 6S 5000 Extremes in the nose bay, and the speed controller sitting on top of the intake ducting. The Spektrum AR9000 is also visible in there.

Photo 8 shows the home-made intake ducts, with the fan mounted behind the wing accessible via a new hatch, and Photo 9 is a close-up of the fan unit in its working position.

Photos 10 & 11 show the unit though the intakes and tailpipe.

Honest guys … its’s an EDF!

Regarding the flap whistle Joe, the flaps are bottom-hinged. I imaging the topside gap just creates turbulence which manifests itself as the whistle. I’ve had bottom-hinged flaps on other models which didn’t whistle though, so I really haven’t a clue.

There is an earlier vid of the 4th test flight which shows me connecting up the battery, and the startup and wind down of the fan unit, when it does sound like more normal rotaing machinery. http://rcuvideos.com/video/Stumax-SM...-EDF-powered-F In this vid the landing had two bunny hops compared with just one for the later vid, so I have improved by 50% during the course of the past 48 landings!

Cheers

Gordon

Gordon W

Hi Pete

Nice to hear from you again! Are you still wild about P-38s? I am. I've bought the Robart P-38 landing gear set and am designing one around the same size as Ziroli's, only much more lightly built for a pair of big Hacker A60 electric outrunners on 12S apiece, with a Benedini sound system.

Just imagine, for an electric propeller ship to sound right, you need to install a Benedini sound system and massive speakers. For an electric jet to sound right, you get away with only the Stumax fan (at least in MW44/P60 size jets) which is amazing.

Gordon

petera38

Hi Gordon,

Great to hear from you again!
Yep- I´m still wild about the P-38, but the last one - a Ziroli - I sold after cutting all the parts - needing some new challenges! It was then I switched to jets.
But I´ve still got one P-38 left - an electric one! I´m looking forward to hearing more about your electric P-38 project.

I´m flirting a bit with EDF, but right now I´m heavily involved with jets and gas turbines.... (old boyhood dream coming true)

Pete