View Full Version : Minimum Flying Speed

Irish Eyes
7th May 2007, 22:42
I'm sure the old hands here can answer this one with their eyes closed but please indulge me all the same.

What is the effect of flying solo as opposed to MTOW on stall speed or minimum flying speed on say a flash11a?

What is the effect of flying solo as opposed to MTOW on takeoff and landing run ditto?

Before anyone says so, I know some who would make MTOW solo :freaked:

Looking forward to some interesting replies.


8th May 2007, 06:31
Hi Liam, I guess this should have been in the training thread, but no matter. As regards stall speed, if we increase the weight in the machine we increase the wing loading. Increase the wing loading and we increase the stall speed. So if our stall speed one up with not too much fuel or ballast on board is 30 mph, add another person and extra fuel and our stall speed will be higher say 36 mph. Flying solo the machine will leave the ground more quickly than at max weight, will nose up rather more upon rotation (as the wheels leave the floor), will climb to circuit height more quickly, and when you level off will require less power to maintain height. When ready to descend into the glide we cut the power at the same point as we would at max weight. When we round out and hold off the aircraft will float for a greater distance when lightly loaded.

With many of the earlier generation flexwings there is an appreciable difference in the feel of the machine between solo and dual occupancy so it is normal practice to carry some ballast on initial solo hours. Gradually reducing this as experience is gained. Hope this helps you get your head around the issue, Chris.

bar shaker
8th May 2007, 09:17

I find that the float lasts longer in heavier aircraft. Perhaps the higher approach speed is part of it, but I also feel there's a momentum issue too.

The speed decay in a light two stroke trike, one up, is very quick once you cut the power.

8th May 2007, 13:23
Looking at this from a different angle to Bar shaker..... A heavy aircraft will float less than a light aircraft, to quantify that statement....... as an Example: A Skyranger with only 1 person of 86kgs will float further than the same aircraft with 2 86kg persons onboard.

The forward momentum on a Skyranger landing at say 45mph with 2x 86kg people will be higher than the same Skyranger with only 1x 86kg person landing at the same speed, but the downward momentum of the aircraft with the 2x 86kg people onboard will also be higher than the aircraft with 1x 86kg person onboard.

So I think that the float is less in a heavier laden aircraft than a lighter laden aircraft, but think that the landing run will be longer on the heavier aircraft, I could be wrong on this and will watch the thread to see how it fares.

8th May 2007, 13:39
Well, I'm going to plump for a third option. It could be either for any particular airplane. I'd also note that I'd expect float to be more dependent on the efficiency of the wing and its position (ie high / low wing as ground effect plays a part in float) than it would on the weight on board. In this case, I'm assuming a constant approach speed, although it would be possible to fly slower at a lighter weight.

Judge Jeremy, can we have a ruling please?

And as to the original question which wasn't asking about float, stall speed goes up with weight, and requires a longer take-off and landing. So flying solo you should be able to take-off and land in a shorter distance, and climb faster for the same flying speed.

Irish Eyes
16th May 2007, 22:52
Belated thanks for your input guys.

I understand the principles involved but was hoping for a more quantifiable answer.

For instance if the minimum landing approach on a F2A is placarded at 42MPH, is this at MTOW or is it at any flying weight at or below the MTOW weight?

Having been airbourne the weight will have decreased due to fuel use if you see what I mean.

I realise that this is a slightly different question but I will get there eventually.