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Comparing Heliptera Propeller with Hoffmann and VH-HDO with ... printer friendly version
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Bob Grimstead
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Gender: Male
Location: Perth, Western Australia or West Sussex, England
Registered: Dec 2006
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Posts: 1411

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Posted Thursday, July 3, 2008 @ 11:36 AM  

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 27C, 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 = 79C
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 Ive 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 20C, 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 = 63C
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 18C, 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 = 58C
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 20C, 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 = 73C
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 its still down on the blue one, and theres still a little wheezing from the valves, so Ill 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]

Jorgen
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Gender: Male
Location: Lund, Sweden
Registered: Apr 2007
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Posts: 725

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Posted Thursday, July 3, 2008 @ 01:53 PM  

Bob,
that's a really neat idea, to keep check on the engine (and the entire aeroplane's) performance to identify and cope with problems early. It could as you pointed out be difficult though to get proper readings, apart from thermals there might still be som ground turbulence at 500 feet which could skew your readings. But I'll start keeping track of cross-wind climbs from 500-1000 feet on days with calm air and try to see if there are some consistency. I usually climb at 70 mph too, so I'll get back when I have some figures.

Take 5(b) just 4 fun/ Jorgen, SE-UDI, SE-XST

Jorgen
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Gender: Male
Location: Lund, Sweden
Registered: Apr 2007
Status: Offline
Posts: 725

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Posted Monday, October 13, 2008 @ 03:38 PM  

Hi,
I have made some timed climbs with the 4, crosswind on fairly stable days, like today. SE-XST does almost exactly 500 fpm from 0 to 2500 ft (1400 cc rectimo, oil cooler and Hoffman 133 fix pitch).

13th October 2008
SE-XST 1400cc Rectimo motor
Aeroplane at medium weight, aerobatic fuel (ca 380 kg)
Hoffman 133 propeller, spinner
OAT 15C, 1018 HPa
Max Static rpm = 2800
Unstick rpm @ 50 mph = 3000
Climbing at 70 mph IAS, altimeter set to 1018 HPa
Time Altitude (ft)
0 0
1 520
2 1050
3 1530
4 2080
5 2470
oil temp at 2500 ft = 80C
cruise at 3200 rpm, IAS = 105 mph
full throttle at 3600 rpm, IAS = 120 mph

Perhaps not the best climb performances, but Im pretty satisfied anyway. I fly mostly from grass strips so I do appreciate that "the toothpick" Hoffman 133 gets me off the ground (make that grass, and sometimes unmowed and moist) in less than 200 m without scorching the prop tips on the weeds. But it sure howls during aeros, as I could hear when a friend tried it out.

Take 5 (b) just 4 fun/ Jrgen

[Edit by Jorgen on Monday, October 13, 2008 @ 03:42 PM]

[Edit by Jorgen on Wednesday, October 29, 2008 @ 01:16 PM]

Bob Grimstead
Captain

Gender: Male
Location: Perth, Western Australia or West Sussex, England
Registered: Dec 2006
Status: Offline
Posts: 1411

Click here to see the profile for Bob Grimstead Visit http://www.redhawksduo.co.uk Send email to Bob Grimstead Send private message to Bob Grimstead Find more posts by Bob Grimstead Edit or delete this message Reply w/Quote
Posted Monday, November 24, 2008 @ 02:07 AM  

Hi guys,

Here's my new, blue Heliptera 52/34 propeller.
Neat, or what?


Yesterday I tried a timed climb. It was windy and thermally, so don't rely ontthe results, but they're not too shabby.
OAT 25C, 1006 HPa, 17 litres fuel aboard, 60-knot (70 mph) climb.
Time Height
0 500
1 960
2 1500
3 2010
4 2540
5 2940

Yours, Bob

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