ETLB Squawk Forums — Archive

Inquiring minds would like to know:
Is it worth it or not to convert?
Pros and cons?
Whats involved?
efficiency?

John
1600R
Pittsburgh

This could be a start , others may add or correct

Pros:
1.Gain some Power
2.Don´t depend on the fan belt

Cons:
1. Have to buy it
2. Can´t stay on the ground for too long

Quoted from Ricardo This could be a start , others may add or correct

Pros:
1.Gain some Power
2.Don´t depend on the fan belt

Cons:
1. Have to buy it
2. Can´t stay on the ground for too long

Their is a lot of information on "Air Cooling" on the old board

"Can't stay on the ground for too long" is incorrect.  Supercowls cool very efficiently even at idle and sitting on the ground.  If anything they run TOO cool.

Tim A.

one advantage of fan cooled is being able to use the output as a heater for winter flying

I like free air...may be a little lighter with free air scoop,power increase, no fan and belt maintance, and no it won't run warm on the ground. Con: may void engine warranty.
Larry

I installed a CPS unit that they sold for the Rotax 447 on my 1100R. The results were all very positive. My CHT problems went away and I certainly never had any problems with temperatures while on the ground. The free air cooling was a great improvement and I would highly recommend it.

Does any body have a pic

Picture....

I'm loving my supercowl. The weight savings is significant and it cools better. Also, less mechanical complexity.

Wasn't there plans on here to build your own at some point?
Does anyone have those plans?

I know it is not ROTAX but if you get hold of a Hirth engine manual they have basic plans for a cooling shroud.  At least it would give you an idea of how it it built.  I have the drawings but not able to access them right now.  I prefer the fiberglass shroud from George...fairly inexpensive and easy to install and maintain.

Tim A.

Quoted from 1564 I'm loving my supercowl. The weight savings is significant and it cools better. Also, less mechanical complexity.

How much weight is the saving?
Will have to do the W&B again.
I just found a used supercowl that will put in my plane.

My weight savings were between 7-9 lbs.  Can't remember the actual number.  I weighed all the parts that were taken off in one pile and the supercowl and hardware in the other pile.  This is how I came up with this number.

I already had a gell cell battery in my plane so I just moved it accordingly to compensate for any CG issues.  I think I moved it forward about 6".

I am adding George's carbon fiber tailspring, fork and Razor wheel and they are much lighter than the aluminum tailspring, steel fork and industrial castor tailwheel.  I will weigh them soon and give report.

Tim A.

Guys, when converting a 447 to free air, are there any gaskets or items that must be purchased? Thanks, Luis.

No extra parts needed if you modify your fan housing.  

If not then you will need the Rotax 910-415 Ignition Housing which is the round ring that hold the recoil starter.  The ignition housing can easily be made by hacking up the fan housing.  Take a hacksaw, die grinder or dremel tool, and tin snips and cut down the fan housing until it looks just like the ignition housing listed above.  The only difference is that there will be a large square hole where the fanbelt traveled through...just turn this hole to the bottom of the airframe (whichever way you mount the engine doesn't matter) as it has many directions it can be mounted.

I have attached photos in another thread but will have to find it.

Tim A.

Just noticed that Rotax lists plans for the cooling shroud for a R447.  It is part number 999-721.  Not sure if they are still available.

Tim A.

http://www.cavediver.com/img/ul/rotax447.pdf
Tim, thanks for the help. If you find the pictures, please post them.