Annual permit renewal check flight in the Jab UL-D

[lee-wave]

In the UK the annual permit to fly check flight needs to be carried out at near to mauw as possible.

 

My strip being marginal at 290 mtrs I first found a 'victim' who weighed around 70kg to be the ballast and then did a solo takeoff at 450 - 70kg = 380kg. I then calculated the extra takeoff length at 450kg using a 10kg/10mtr ratio and then carried out the second fully loaded 'check flight'.

 

The 2 flights were only a half hour apart as you can see from the suns position so ambient conditions were near to identical with about 5 knots of right hand x wind, 23C and 1013 HPa. Lift off for both flights was 53 knots and the speed allowed to increase to 68 knots for the climb out. Flaps were at the first detent. I estimated 2-3 litres fuel burned for the 380 kg flight so the second flight was around 447kg.

 

Unfortunately a cow just about blocked the exact lift off point for the 447kg takeoff but you can see how much flatter the heavier take off was using the tree as a reference point (the sun was also lower in the sky). After the test flight I paced the extra takeoff length and it was roughly 90 mtrs ± 5mtrs....a lot further then calculated....something I thought about later over a beer.

[skippydiesel]

Other than being unsightly and smelly (an odour I dont mind) does the risk of cow pats coating your empennage worry you??

[NT5224]

Hey, thanks found this really interesting. Great to see you operating out of 290 metres in a Jabiru.

 

Alan

[lee-wave]

Other than being unsightly and smelly (an odour I dont mind) does the risk of cow pats coating your empennage worry you??

When the weather is good for flying I communicate with the farmer...the day before flying the cows are moved off the strip. There is an electric fence post which runs a wire down the length of the strip and toward the windsock on the left. In the morning I roll the strip. You can see the rolled section of the strip. This flattens the cow pats and very little is flung up onto the aircraft. I try not to taxi over long grass which does no good to the prop tips...in fact does anyone have a spare 60" x 42" Jab prop floating around?

 

Thanks Alan....

For the price / performance ratio of the Jabiru I believe there is no finer microlight aircraft available....being of composite construction it can live outdoors all the year round with covers....it can cruise at 90 knts burning just on 15ltr/hr. The take off and landing performance is outstanding for a true 80 hp motor. The only other similar aircraft of composite construction and performance is the Pipistrel Virus which costs 3-4 times as much even for a second hand example. In these strange times the Jabiru keeps me sane and socially distanced from my fellow human beings......