Hi,

A few months ago I bought a Wren Turboprop kit, an impressive piece of engineering.

After sspending many hours balancing both the Gas Generator and Power Turbines by hand, they were fitted and the whole engine assembled.

After a few teething engine runs I noticed a vibration....so off came the prop and blalanced that too.

Prop back on and then the "buzz" became apparent.

As I was going home to Australia on holidays, I decided to take both Turbine assemblies and get them electronically balanced by Perth R/C Models in Perth, WAestern Australia.

They balanced the "way-out" Turbines, for a very reasonable price.

I re-installed the Turbines and on start up the engine lit-up on the gas, but the rpm hung at 16,000 rpm and they was fuel dripping from the exhaust....not normal.

So back to the books....nothing....watched some TV and then it came to me.

On the Reduction Gearbox there are Cooling Air and Fuel Lube Festo connections for the Power Turbine....guess who had them connected around the wrong way.

So lines swapped over....now it was dark....so it's time for our first night start.

Throttle up and down, here goes the priming run....now the started engages....the Lube pump starts....pop goes the gas....Yippee the fuel valve opens and we have fuel ignition and here she accelerates to idle at 45k....Phew!!!

Lesson to be learned....be careful with the connections....yes, the Festo connections do have "Air" and "Fuel" stamped on them....but who reads instructions....

Try a night start....mine was wet with fuel, so I got some nice flames from the exhausts....neato.

Happy Flying...and read those instructions...

Nige

Hi Nigel,

Glad to hear you sorted out your little gremlins.
What model are you going to stick it in and how big a prop can it swing ?

I saw a similar combo in a "turbo raven" aerobatic plane, it was great !

Can you post a larger picture of your rig please ?, your avatar logo looks very interesting.

Hi,

Yeah, sure was good to get her going again.

As for an airframe, I getting info together to build a 50% BD-5 with a pusher prop.

As for thrust it'll put out 35-40 pounds thrust with a 3 blade 21x10 prop.

Perth R/C are also working on a Jetranger Helicopter and also a Pilatus PC9 to use the Wren Turbo in.

Sure, I'll take some pix tonight and post them.

Nige

Before you get busy on making a 50% BD 5, at Lubbock a plug was displayed for a 50% BD5 which is now done and ready to make a mold!! Built by Tom Sewell, this thing was massive! The canopy was something like 3 and half foot long. It may be a year, I don't know what's gonna happen with it, but it should be a very impressive aircraft.

Sean

Would these be from that plug?

Seen at Heart of Ohio this past weekend.

...jim

That looks like the 40% one to me. Do you know what the wingspan of those were?

Do any of you guy's know the size if the real BD5J??? 50% is a huge turbine poject.. The 50% model is a reality, and will fly next spring.. I have seen the plug. As we all know, the bigger the better they fly.. Tom has done his homework and i think it's gonna be way cool!!

Danno

the "full scale" ( if we can say that!!) BD5J is 13.26 ft long and has a wingspan of 17 ft.
The datas will change for other BDs up to 14.68 ft long for the BD5T and 21.5 ft wingspan for the 5B.
There are alot of info on www.bd-micro.com

When will we see a full scale BD powered by 4 AMTs or JETCATs???