changing old wooden prop to a new composite one?

[Bruce Tuncks]

I am still operating with the original wooden/composite prop. But I notice that all the new Jabirus have a nice-looking black adjustable prop.

Has anybody swapped their wooden prop for one of the new ones? If so, please tell us what you noticed.

[kgwilson]

Jabiru composite props are manufactured by Bolly to Jabirus specs. I replaced my wooden prop with a Bolly Bos 5 carbon fibre/kevlar/composite prop on my 3300A engine. This is not the same as the Jabiru model & has a completely different hub. The old wooden prop was always getting stone chips & nicks from just about anything. I'd put some leading edge tape on it but it still kept on happening. At first I had the pitch too coarse, then too fine. After 4 adjustments got it so WOT straight & level was 3300 rpm. Top speed increased by almost 30 knots, cruise by 20. Full power climb at 80 knots is 1100-1500 fpm 1 up depending on the conditions. One major benefit is the torus curve at the root which has reduced temperatures quite noticeably even though they were good with the wooden prop. The Jabiru spec prop does not have these. My big issue was having to modify the cowl so the torus didn't hit it.

 

I have 50 hours with this prop and no nicks or chips at all. Fantastic prop from an excellent Australian manufacturer.

 

In saying all this the old wooden prop which now decorates the wall of my hangar was not much chop. I got it for nothing after destroying the first wooden prop & it was not as good as the first one even though it looked identical.

 

Jab owners around here reckon the Jab spec composite props are way better than wooden ones. There have been a number of delaminations of Jab wooden props.

[Guest Machtuk]

Do Google search on Patroney props.

[waraton]

I'm currently up for a new prop on a Jab 230. Phone numbers I have for Rob Patroney are disconnected. Aircraft has been running a patroney 2 blade for 10 years and has given good service. Am interested to hear more about the Bolly Bos 5.

[Bruce Tuncks]

They have obviously improved since a 3 bladed Bolly prop lost a blade when trying out on a Jabiru. The pilot did a good job, but the main thing was that the engine stopped because the plug leads tore out , just before the whole engine was lost from the plane.

Losing your engine would sure put the C of G behind the aft limit huh. I wonder if you kept the speed up if it would be controllable enough to land in this configuration.

This story made me scared of props like this. Now I think that the new props are really ok and I am missing out on benefits like kgwilson described.

[Nobags]

Jabiru composite props are manufactured by Bolly to Jabirus specs. I replaced my wooden prop with a Bolly Bos 5 carbon fibre/kevlar/composite prop on my 3300A engine. This is not the same as the Jabiru model & has a completely different hub. The old wooden prop was always getting stone chips & nicks from just about anything. I'd put some leading edge tape on it but it still kept on happening. At first I had the pitch too coarse, then too fine. After 4 adjustments got it so WOT straight & level was 3300 rpm. Top speed increased by almost 30 knots, cruise by 20. Full power climb at 80 knots is 1100-1500 fpm 1 up depending on the conditions. One major benefit is the torus curve at the root which has reduced temperatures quite noticeably even though they were good with the wooden prop. The Jabiru spec prop does not have these. My big issue was having to modify the cowl so the torus didn't hit it.

 

I have 50 hours with this prop and no nicks or chips at all. Fantastic prop from an excellent Australian manufacturer.

 

In saying all this the old wooden prop which now decorates the wall of my hangar was not much chop. I got it for nothing after destroying the first wooden prop & it was not as good as the first one even though it looked identical.

 

Jab owners around here reckon the Jab spec composite props are way better than wooden ones. There have been a number of delaminations of Jab wooden props.

What happened to your take off roll?

[kgwilson]

Takeoff roll was a bit better when the pitch was fine. Not a lot though. If I was running a smaller engine the difference would be more noticeable. I've never measured the roll length though it is supposed to be about 180 metres which is probably close. The strip is 1200 metres long, I rotate at 40-45 knots & I am usually close to 400 feet by the end when there is little or no wind. Speed by then is about 70 knots & I reduce climb angle to achieve 80 knots for the remainder of the climb.

[derekliston]

I have the Jabiru composite prop on my Jab 2200 engined Zenith CH701. It was pitched by Jabiru to suit the airframe. I see 3010 static rpm and about 2960 on climb out at 50 kts. I am quite happy with the set up.

[facthunter]

IF you chuck a blade the engine will usually come out and the plane will be too tail heavy to control. There was a chipmunk did that near lake Macquarie and it spun in gently due to less weight. The prop was a Fairey-Reed two blade metal one and cracks were quite common near the hub which was covered by a spinner.

Wood props are easy on the motor but it's accepted they are inevitably less efficient and flying in rain will damage them. Where a type had either as an option, many pilots felt the wood prop was less harsh from an in the cabin perspective.

What happened to the Sensenich composite for the Jabiru? Nev

[Guest Machtuk]

I operate both CS Hartzell & CF (ground adjustable) props on my planes, all props are a trade off of some description.

[Old Koreelah]

... the main thing was that the engine stopped because the plug leads tore out , just before the whole engine was lost from the plane.

Losing your engine would sure put the C of G behind the aft limit huh...

 

Good point, Bruce. I've read of Rotax engines vibrating so badly on losing a prop blade that carbies are ripped out of their rubber mounts, thus stopping the engine before it removes itself from the airframe.

So unclamped carbies may be a clever design feature.

[Thruster88]

Good point, Bruce. I've read of Rotax engines vibrating so badly on losing a prop blade that carbies are ripped out of their rubber mounts, thus stopping the engine before it removes itself from the airframe.

So that unclamped carbies may be a clever design feature.

 

$hit happens

[wideblueyonder]

I am still operating with the original wooden/composite prop. But I notice that all the new Jabirus have a nice-looking black adjustable prop.

Has anybody swapped their wooden prop for one of the new ones? If so, please tell us what you noticed.

Hi Bruce,

I swapped my Jabiru wooden prop for a new black composite prop from Jabiru some 5 years ago on my J-120.

Mine was not set and pinned by the factory so I was able to pitch it to suit my needs a bit better.

I set it to get 3300rpm straight and level at wide open throttle. (set for best climb).

Could not be happier!

Quieter, more efficient, shorter take-off roll, less fuel burn, similar cruise, better climb, stays in balance, no damage from taxying over animal droppings, polishes up easy with your favourite furniture polish to keep it looking as new!

Everyone comments on how sweet it sounds.

If my calculations are right after a trip to Temora and back, I get the equivalent in car talk of 7 litres per 100kms at an easy 100kts. (13 lph)

You will need a new spinner, prop bolts etc. I also used a Dynavibe to balance it to 0.03 ips

WBY

[jetjr]

2200 have strong inherant vibration/harmonics, several nasty problems with aftermarket props over the years. Wood absorbs these but has its problems.

More rigid carbon props cant handle this well hence why Jabiru version is actually fibreglass

the 3300 doent have this harmonics problem as much and many CF props like those from Patroney and Bolly work well

Caution seems to be needed with over propping for speed as can load engine too highly, causes temp and fuel problems that's why Jabiru pin the pitch

Ive run several types on a 3300, 5x, and the pick is Bolly 2 blade adjustable (ive not had Jabiru fibreglass one)

I believe Rob Patroney no longer makes props, they are good however heavy Ive been told.

[Guest Machtuk]

2200 have strong inherant vibration/harmonics, several nasty problems with aftermarket props over the years. Wood absorbs these but has its problems.

More rigid carbon props cant handle this well hence why Jabiru version is actually fibreglass

the 3300 doent have this harmonics problem as much and many CF props like those from Patroney and Bolly work well

Caution seems to be needed with over propping for speed as can load engine too highly, causes temp and fuel problems that's why Jabiru pin the pitch

Ive run several types on a 3300, 5x, and the pick is Bolly 2 blade adjustable (ive not had Jabiru fibreglass one)

I believe Rob Patroney no longer makes props, they are good however heavy Ive been told.

 

I have an adjustable Patroney prop on my 2200A, runs sweet after a few hundred hours?

[facthunter]

There's no doubt a wood prop will not be as efficient as other alternatives.. Matching any prop to your engine airspeed combination is still the biggest factor. I've seen a few fiddle a lot and revert to the original in desperation. Jabiru have always stressed not to overprop the engines. It's a bit like getting into top gear too early and making the engine LUG excessively. Blade area is more important on draggy planes. Tooth picks might work on fast(er) items. A good C/S is all well and good if you are cruising over say 125 knots but weight , cost and complexity have to be taken into consideration if you are practical about it.. You CAN make your own wood prop and not be a risk if it's 2 blade and sensibly proportioned. Nev

[Old Koreelah]

...Jabiru have always stressed not to overprop the engines. It's a bit like getting into top gear too early and making the engine LUG excessively....

I asked a highly-respected LAME how all the engines he maintains never seemed to suffer thru bolt problems. He was careful to avoid loading the prop, because that could lead to detonation, a very effective way of demolishing light engines.

[derekliston]

IF you chuck a blade the engine will usually come out and the plane will be too tail heavy to control. There was a chipmunk did that near lake Macquarie and it spun in gently due to less weight. The prop was a Fairey-Reed two blade metal one and cracks were quite common near the hub which was covered by a spinner.

Wood props are easy on the motor but it's accepted they are inevitably less efficient and flying in rain will damage them. Where a type had either as an option, many pilots felt the wood prop was less harsh from an in the cabin perspective.

What happened to the Sensenich composite for the Jabiru? Nev

A lot of dedicated aerobatic aeroplanes in the UK have a steel cable around the engine from one firewall engine mount bolt to the diagonally opposite one for the purpose of maintaining tolerable CofG should the engine break free.