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Archive for February, 2015
Posted by solentlife | Feb 18, 2015 @ 03:17 AM | 79,376 Views
Recently a tussle has been on here about use of tapered reamers and the misconceptions of some about them.

APC Prop company recc'd tapered reamers for very good reason and go to the level of explicit instructions how to ream a prop.

OK lets look at Tapered Reamers.

There are basically 3 types ....

Hobby shop variety which double as 'cutters' for Lexan and various plastics. Doubtful quality and blunt easily.

Repair / Carpenters Reamers. These are generally in Carbon Steel and an excellent economic long lasting tool. Available in various tapers and size ranges.

Machinists precision Reamers usually also in Carbon Steel and Case hardened. Produced for precision work in hard materials. The most expensive of the reamers and in reality unnecessary.

As APC show in their illustrations, the taper is purely to allow shaft to pass through and for rear shaft hole and hub to center correctly. They eveeven illustrate how to over-ream and insert shaft ring to fit shaft exact.

This shows that the second type of reamer is fully suitable for the job.

I have reamed many props this way and always found it to work as designed. I have even balanced props before reaming to check if any change after .... no change at all. Balance remained correct.

I have placed my Reamer on a dial meter and found that the flutes are accurate and there is no reason to expect the cut would be out of true.

Please note that I do not discuss stepped reamers - they are fine and some are...Continue Reading
Posted by solentlife | Feb 18, 2015 @ 02:54 AM | 78,119 Views
Finally the ASP FS91 arrives and with slight modification to firewall - is fitted. The cylinder head is not far of same position as the old OS FL70 so all I needed to do is cut a new needle hole - this time is much better being at top instead of underneath as that 70.
As my usual practice ... low speed needle left as factory, high speed set at 2.5 turns to initial start. Finger over exhaust, I had removed the choke gear as there was not enough room behind to firewall, flipped till I was cconfident fuel was to carb. Connected glow and flipped by hand - she kicked hard ! Decided to play safe and put starter on her. She started instantly. Few clicks in on high speed needle and she was running nice, rich a touch for first time. Ran about 1/2 tank through at various throttles, then let her cool. Prop is a 14*7 APC glow.
Started her again ... then put her in the air. I prefer to break in my engines in the air.

She immediately showed how much better thathan the 70 she is. Even though I was careful with needle setting and throttle. This is one model that I know will improve as that engine beds in.

So what is the other model ? Its the Hyperion 44.4" electric Yak 55. Sold by Hobby King. I fitted a 3542 1000kv with 45A ESC ..... initially a 10*6 prop as I was waiting for the 11*7 I intended to use.
I decided to split the elevators with 9gr metal gear servos, rudder with 16gr, ailerons with split 12gr's. The aileron servos immediately gave problem as they are digital and I...Continue Reading