View Full Version : RAF style towers for AC
11-10-2004, 02:27 AM
Here is a pic of my new towers. The round top one is my AC towers with a bolt height of 4 1/4" with the RAF style bearings installed.
The blue one is a stock RAF tower.
The tall one is my new RAF style with 4 holes for my double bearing rotorhead. The top has also been extended to accept the RAF spreader & teeter stops without interference.
The main reason I had these made is to try a set of RAF 30' blades without having any fitting problems. The bolt height is 4 3/4", the same as stock RAF towers.
If the RAF blades lift better then I will sell my 28' SC blades & order 30'SC's with the taller hub block.
I will still need to see about the side to side play, & shim accordingly.
11-10-2004, 03:47 AM
Chris; Looks good..... :)
11-10-2004, 08:24 AM
You have a knack for R&D!
11-10-2004, 10:38 AM
Some suggestions if you will:
If your bearing block is the same dimension as RAF,
If you have the RAF hubbar,
If your going to use the SC hubbar with the RAF towers;
Use your calipers and measure across the chordwise screw of the RAF hubbar.
Now measure across the SC hubbar.
The difference between the two measurements will be the amount of shim you need. I'm sure you won't have any slop after properly installing the spreader.
11-11-2004, 01:39 AM
Thanks guys. I will be posting all of the measurements & pics. I have off work tommorrow, & hope to do some fitup & flying. Man, I hate winter & daylight savings!
11-12-2004, 01:26 AM
Not sure, I'll ask Air Command.
11-15-2004, 02:52 AM
I did some measuring of hub block widths yesterday. 3 DW hubs all measured 2.5" wide, within a few thousandths.
My SC hub also measured 2.5" wide.
My SC hub block measured appx. 3.2" from top of hub bar to top of block.
This put the center of teeter bolt hole at 2.54" from hub bar to center of hole.
11-15-2004, 03:20 AM
Test fit new towers. SC hub block needs to be taller to work with these. WAY too much teeter. Remember, these were made to fit the stock RAF height. But even with this much teeter action the hub block did not even get near the spreader.
I then installed my AC towers with the RAF style teeter bearing assemblies. No shims will be needed. When the teeter bolt is drawn up , even finger tight, the bushings contact the rotor hub with no side to side slop! PERFECT !
One problem.... with the taller towers installed, I will not be able to get it out the hangar door !! Get the chainsaw !
The last pic is to compare the RAF teeter bushings with the original AC ones.
The AC bushings are shorter, which caused me to pull the towers inward when I tightened the bolt. They should have been shimmed.
Does anyone have the block measurements for the 30' SC blades designed to replace the RAF blades? I imagine they will be close to the RAF measurements.
I will post the RAF measurements when I see them again.
11-26-2004, 03:10 PM
How are the Dragon Wings working out? Are they not as working the wat you wanted? It looks ike many things have changed since ROC...
How are those take offs now?????
11-27-2004, 10:06 AM
I think your on the right track now Chris. I don't see any problems ahead.
Keep us posted.
11-27-2004, 05:05 PM
I think Chris is just wanting to try a set of 30 foot RAF blades to see if going from a 28 foot dragon wing or Sportcopter rotor to the 30 foot RAF blades will allow him to get a better rate of climb with his current engine to weight ratio. He is going to alot of trouble to test these blades!!!..... But let's hope it helps.
11-27-2004, 07:01 PM
Chris: I had a good set of the latest generation RAF blades. I can assure you the Sportcopters I have are without a doubt 10-12 mph faster. The climb rate is much better.....the landings have more reserve ....
It just feels like I really have a cross country machine with this extra speed. I can easily cruise at 80 actual ground speed....with less rpm's than I used to cruise at 70 with my RAF blades. If I want to cruise at 4700 rpm...it will average 83 groundspeed. If I want to cruise at 4800..which is the most I want to cruise at...I get actual gps average groundspeeds of 85-86 mph. I am much more content with cruising at 4600 rpm..and averaging 80 mph and saving my engine and fuel. I love it.... :)
I am still playing with my chordblock adjustment. I have passed the sweet spot and now each flight is getting more stick shake. I am just doing this for my personal documentation. I like numbers..and I will soon be going back to my smoothest chordblock setting...then track the blades.
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