CFM Glint

I have a particular interest in ducted fans, as I was asked once to develop a design proposal, to replace a three bladed pusher propellor driven by a Rotax engine with a ducted fan.

The aircraft was to be called the CFM Glint. I will post a drawing of it here soon. It was a flying wing, designed and developed by a friend called David Cook, of CFM Shadow Ultralight fame. Only one was made, but it never got to the stage where the fan was installed. I believe that the aircraft still exists, but was never flown.

“RobAnt: The CC2(N1) looks very interesting – given it’s date, you can’t help but wonder what would have been achieved by further development as technology improved.”

This was a dead-end technology unfortunately, quickly surpassed by the jet engine. A ducted fan offered no advantages over free propellor driven aircraft. It had less acceleration, much higher fuel consumption, less range, and poorer acceleration. The gas turbine was the holy grail technology.

Ducted fans compared to free props.

Hi RobAnt

Pay attention, here’s the science bit… 😉

If any one comes up with some model aircraft comparisons, I will be intersted. Because of Reynolds number, air density, skin friction, etc, aerodynamics does not scale as you might expect between very small models, and full scale applications, so for a full scale application:

Advantages of a ducted fan over a free prop.

Better ground handling safety. Quieter, fan blade tips can run with reduced losses in theory because the duct can hug the fan with minimal gap.

Advantages of a free prop over a ducted fan.

A free prop will draw in a larger volume of air, for the same disc diameter, and will therefor produce greater thrust. It is a lighter assembly. It will produce less drag. It will have better fuel consumption correspondingly. A free prop has more static thrust, which is better for take-off, and general acceleration.

Also, for a ducted fan to produce the same thrust as a free prop it has to turn faster, hence worse fuel consumption.

Cockpit-fest 2006

Hi Stuart

Just the basic Hornet panel this year…It’s a logistical thing!
I now have a growing collection of shaped wooden parts, but no-where near assembled. None of which looks like a cockpit yet either. I’m aiming for the 2007 event for a more substantial display.

Besides, I thought that showing a few more panels wouldn’t go amiss, and may encourage others to do the same too. It would be nice to be part of a line up as I have previously mentioned aswell.

Aviation Traders

I used to work with an airframe designer (now retired) who worked at Aviation Traders, Southend. I believe he was the principle designer on the Mystery Jet, and formerly of Handley Page. From an early stage in the development program it was shown that the take-off and landing speeds would have been unfeasibly high, owing to the heavier wing loading than even a fully equipped T.11 with ejector seats, guns, ammunition, etc. Coupled with the requirement to retain standard wings, booms, and undercarriage, this made the project unfeasible.

Shame, as this was a nice concept that could have utilised a lot of the vampires then coming out of service with the military, and to provide a neat little business jet.

Wreckage ID

Hi Rocketeer

I’ve found an aircraft leading edge on Sizewell beach several years ago and identified it as being from a “US aircraft” by the type of rivets used and the size of section.

Did you get any photos of the parts from Felixtowe? I will photo the leading edge and post here.

Correction

dhfan – “Isn’t it 2.1/2?”

W4050 Prototype – Complete/Under restoration
TA122 F.B.VI – Complete/Under restoration
TA634 TT.35/B.35 – Complete/diplayed
TJ118 TT.35/B.35 – Fuselage only/dismantled

= 3.5 mosquitos.

🙂

Credit, where credit’s due.

Fantastic project Tony.

Can you say yet which of your projects you are intending to bring to this years Cockpitfest? I missed the Hurricanes appearence.