Posted Thursday, July 3, 2008 @ 12:36 PM
In preparation for fitting my 1750cc engine in the blue Fournier, I got a new, coarser propeller made by Mike Ellinas of Heliptera Propellers RMB 5888 Kerrisdale, Vic 3660 Australia. heliptera@bigpond.com
Being curious, I tried it out on the 1400cc motor.
It was only two knots slower than the RF5 prop, but at 300 fewer rpm.
But it climbed pretty much as well: 680 fpm from 0 to 680 feet, against 600 fpm from 500 to 1500 feet for the RF5 prop
Test Flying Heliptera 52 x 36 propeller
19th April 2008
VH-HDO 1400cc Rectimo motor
Aeroplane at max weight, full fuel (390 kg)
Heliptera 52 x 36 propeller, no spinner
OAT 27°C, 1014 HPa
Max Static rpm = 2675
Unstick rpm @ 40 knots = 2750
Climbing at 60 knots IAS, altimeter set to 1013 HPa
Time Altitude (ft)
0 0
1 680
2 1230
3 1700
4 2300
5 2830
oil temp at 3,000 ft = 79°C
full throttle speed at 1,500 ft = 108 kt (124 mph) 3300 rpm
at 3200 rpm, IAS = 104 kt (120 mph)
at 2200 rpm, IAS = 63 kt (72 mph)
During aerobatics it is MUCH quieter than all previous propellers I’ve tried – because of its coarse pitch and low rpm, of course.
So, I took it to England to try on the red aeroplane, which was currently fitted with a Lodge 52 x 27.5 prop.
With its comparatively new engine (less than 100 hours STOH), I hoped this would perform even better with the Heliptera prop.
Test Flying Lodge 52 x 27.5 propeller
6th June 2008
G-AWGN 1400cc VW motor
Aeroplane at max weight, full fuel (390 kg)
Lodge 52 x 27.5 propeller, no spinner
OAT 20°C, 1013 HPa
Max Static rpm = 3300 indicated (v dodgy Westach tacho)
Unstick rpm @ 40 mph = 3300
Climbing at 60 knots IAS, altimeter set to 1013 HPa
Time Altitude (ft)
1 500
2 920
3 1360
4 1770
5 2200
6 2600
oil temp at 3,000 ft = 63°C
full throttle speed at 1,500 ft = 113 mph (98 kt) 3600 rpm
at 3200 rpm, IAS = 87 mph (76 kt)
at 2400 rpm, IAS = 67 mph (58 kt)
Imagine my disappointment at these results!
Test Flying Heliptera 52 x 36 propeller
6th June 2008
G-AWGN 1400cc VW motor
Aeroplane at max weight, full fuel (390 kg)
Heliptera 52 x 36 propeller, no spinner
OAT 18°C, 1013 HPa
Max Static rpm = 3100 indicated (dodgy Westach tacho)
Unstick rpm @ 40 mph = 3100
Climbing at 70 mph IAS, altimeter set to 1013 HPa
Time Altitude (ft)
0 500
1 960
2 1440
3 1940
4 2440
5 2870
oil temp at 3,000 ft = 58°C
full throttle speed at 1,500 ft = 114 mph (99 kt) 3600 rpm
at 3200 rpm, IAS = 110 mph (96 kt)
at 2400 rpm, IAS = 79 mph (69 kt)
So… I whipped off the cylinder heads (I had to do this anyway, due to missing baffles) ground the exhaust valves with fine paste and re-set the valve clearances. They were between .025 and .040 inch, but despite these wide gaps, no individual cam lobe appears particularly worn.
I checked the ignition timing (it was fine) and spark plug colours (left bank v slightly lean). Also got ASI and altimeter calibrated – they were OK, within 2 mph and 20 feet – and tried again.
Test Flying Heliptera 52 x 36 propeller
23rd June 2008
G-AWGN 1400cc VW motor
Aeroplane at max weight, full fuel (390 kg)
Heliptera 52 x 36 propeller, no spinner
OAT 20°C, 1014 HPa
Max Static rpm = 3100 indicated (dodgy Westach tacho)
Unstick rpm @ 40 mph = 3100
Climbing at 70 mph IAS, altimeter set to 1013 HPa
Time Altitude (ft)
0 500
1 1080
2 1660
3 2180
4 2620
5 3040
oil temp at 3,000 ft = 73°C
full throttle speed at 1,500 ft = 118 mph (103 kt) 3600 rpm
at 3200 rpm, IAS = 102 mph (89 kt)
at 2400 rpm, IAS = 67 mph (58 kt)
So its performance is getting better, but it’s still down on the blue one, and there’s still a little wheezing from the valves, so I’ll do them (all) again properly (and see what I mean about speeds other than full-throttle speed being rubbish).
Careful test flying can be very revelaing, and indicates the condition of your aeroplane, as well as comparative propeller performance.
For that reason, on ALL flights I hit the stopwatch as I climb through 500 feet to see what the climb rate is after one minute has elapsed. I want to know if my engine is down on power, especially if I am about to fly a low-level aerobatic sequence!
Let us know some of your propellers performance.
Yours, Bob
[size=small][Edit by Bob Grimstead on [TIME]1215103044[/TIME]][/size]