MTV-9 Versus Hartzell ‘Claw’

Although a lot is spoken about the comparative performance of propellers, it is seldom that propellers are genuinely tested on a ‘back to back’ basis; with a skilled pilot who can duplicate the flight; with adjustments for standard atmospheric conditions and with proper measuring equipment.

Although the following test was done at the premises of MT Propeller, we emphasise that the results are totally objective; were verified by Alex Maclean , who as an independent pilot has no bias – indeed he has just spent his own money to buy the Edge aircraft which was used as the test aircraft, and fitted with the HC ‘Claw.’

Propellers

The latest HC ‘Claw’ – model HC-C3YR-1A/7690E. 

The MT propeller is the new wide-chord MTV-9-B-C/C198-25.  (The –25 at the end signifies the new blade profile.  A similar (but still slightly different profile), the –29 is used on the larger MTV-9 propellers as fitted to the Russian M14P engine).

Bo th are 3-blade propellers of 198cm diameter.

Aircraft

The aircraft was an EDGE 540 (registration number N-540WC).

The pilot

Alex Maclean – a well known aerobatic pilot; member of the Spanish Aerobatic Team; current Red Bull competitor.

Location

Tests were done at MT Propeller, over 1½ days in a totally controlled fashion.  That is all flights were repeated; all results corrected for standard conditions.

Also the propeller speed was varied by adjusting the governor to see if this made a difference (see below).

Weights

Bo th propellers were weighed in an ‘as fitted’ fashion, including spinners and mounting bolts etc.

Static Thrust

Top Speed

Acceleration

Starting at 89 knots (calibrated air speed), after 10 seconds with the HC ‘Claw’ speed was 140 knots and the MTV-9 145 knots.

From 89 knots in 20 seconds the HC ‘Claw’ reached 160 knots at 2800rpm.

(Using 2,850 rpm, the HC ‘Claw’ was slightly slower).

From 89 knots in 20 seconds the MTV-9 reached 165 knots at 2800rpm.

Using 2850rpm, in 20 seconds from 80 knots the MTV-9 reached 170 knots in 20 seconds.

MT Advantages

There are other advantages of MT Propellers by virtue of their combined wood/composite structure construction, which include:

Ø      The ability to repair blades after damage – including, even, loss of a tip.

Ø      Greater smoothness through intrinsic vibration damping.

Also the MTV provides considerably greater drag in fine-pitch for deceleration in aerobatics.

Price

Despite a recent price increase, the MTV-9 is under half the price of the HC ‘Claw.’

Do contact us if you need more information.

 

17th July 2006