The stall speed at 2200lbs (two adults, 3 hours fuel) is 39 KIAS (38KTAS) with full flap and 46 KIAS flaps up. At 2500lbs it is 46KIAS (46KTAS) with full flap and 50 KIAS flaps up. This is with Vortex generators installed which lower the stall speed about 2-5 KTS. Position error (between IAS and TAS) is less than 2 KTS at all speeds.
Thanks for that. I am curious as to what approach speed you use. In my Bearhawk 4...I have to approach at 80mph...75 over the fence..otherwise she gets very tail heavy and have to use a lot of power to drag it in...not nice...I have an IO390. 210hp engine...all the above with one pilot and 3 hrs fuel and a handful of bits.
Your engine combination is probably the holy grail balance between power, weight, and CG. Those speeds you are using will give a nice safe margin on approach too, but won't allow a very short landing. Do you have VG's installed? There's a number of factors in getting the lower approach speeds safely. Having VG's lowers the stall speed a couple of knots and gives improved low speed handling characteristics. Also, how heavy is your BH in roll (if it's quite heavy then the ailerons might not be reflexed). The usual recommendation is to reflex the ailerons 3/8" (very easy to do if not already done) which makes them lighter in roll response, reduces adverse yaw (a little) and gives improved stall characteristics - meaning the tip stall will be delayed. These contribute to a safer margin at low speed. Additionally, flying at a CG forward of around 14" means elevator authority is easily lost at idle power and below 55 kts due to not enough airflow over the tailplane to counteract the forward weight. It's self correcting (but takes a couple of hundred feet) or adding power provides enough prop wash over the elevator's to regain authority. It feels like a docile stall and it's given a number of BH pilots a fright. It's less likely with a 4 cylinder engine (yours) because the CG is usually further aft than if you have a 540 up front. If the above are sorted, then a lower speed approach can be flown with F3 or F4. Assuming normal flap rigging, the only difference is that F4 adds more drag (but doesn't change the stall speed). Having more drag enables you to carry a little more power and retain a little more elevator control. The key is to keep power on. Flap rigging can vary a bit between builders and is felt by how hard it is to pull the flap handle. Slow initially to 50kts (60mph) while maintaining straight and level. You'll have to raise the nose to do this. It will feel like you're practicing a stall entry. Compared to an actual stall, the nose would be higher again so it's good to compare the two. When the engine cowling (prop spinner) is just touching the horizon, add just enough power to hold it there and then start a gentle descent with the spinner still touching the horizon. That's the pitch attitude to go for. You should find that the airspeed is still above the stall speed by about 1.3x. After practice you tend to stop watching airspeed and just watch the pitch attitude, but that took me many hundreds of landings. Best to do this with a competent instructor or another pilot who is well versed in STOL ops until you get the hang of it, and start at higher altitude. Do a few stalls too, so you can recognize the difference between the two. The full stall attitude with power on usually occurs at a pitch attitude above the 3-point attitude, so if you're crossing the fence and gently raising the nose, the feeling is like trying to drag the tail wheel onto the ground. That will put you right on the edge of the stall. One thing to be aware of is that at low speeds there isn't always enough energy to flare the aircraft, so in that case you need to add power to flare. This all took me a while to learn.....baby steps......stay safe, have fun. These's a lot more BH specific info here www.bearhawkblog.com/tail-wheel-training and in the articles section. You'll also find a contact for me there if you'd like to email.
One thing to add, is when discussing speeds, there's an assumption that our speeds are all checked for position error. Usually they are not. So what I'm calling 50KIAS could show as 55KIAS on yours for example. Best to target the pitch attitude and find your aircraft's own happy place.
Excellent stuff bro, respect
Great video ! awesome work.
Ello Oklahoma bois ! I remember meetin ya this year and I just wanna say hi ! Maybe take me on a tour sometime soon ?
Lookin good. 👌🏼
😎😎👍
What were your IAS at those stalls.
The stall speed at 2200lbs (two adults, 3 hours fuel) is 39 KIAS (38KTAS) with full flap and 46 KIAS flaps up.
At 2500lbs it is 46KIAS (46KTAS) with full flap and 50 KIAS flaps up. This is with Vortex generators installed which lower the stall speed about 2-5 KTS. Position error (between IAS and TAS) is less than 2 KTS at all speeds.
Thanks for that. I am curious as to what approach speed you use. In my Bearhawk 4...I have to approach at 80mph...75 over the fence..otherwise she gets very tail heavy and have to use a lot of power to drag it in...not nice...I have an IO390. 210hp engine...all the above with one pilot and 3 hrs fuel and a handful of bits.
Hence I only use 3rd stage of flap at the last seconds because of Vfe speeds
Your engine combination is probably the holy grail balance between power, weight, and CG. Those speeds you are using will give a nice safe margin on approach too, but won't allow a very short landing. Do you have VG's installed? There's a number of factors in getting the lower approach speeds safely. Having VG's lowers the stall speed a couple of knots and gives improved low speed handling characteristics. Also, how heavy is your BH in roll (if it's quite heavy then the ailerons might not be reflexed). The usual recommendation is to reflex the ailerons 3/8" (very easy to do if not already done) which makes them lighter in roll response, reduces adverse yaw (a little) and gives improved stall characteristics - meaning the tip stall will be delayed. These contribute to a safer margin at low speed.
Additionally, flying at a CG forward of around 14" means elevator authority is easily lost at idle power and below 55 kts due to not enough airflow over the tailplane to counteract the forward weight. It's self correcting (but takes a couple of hundred feet) or adding power provides enough prop wash over the elevator's to regain authority. It feels like a docile stall and it's given a number of BH pilots a fright. It's less likely with a 4 cylinder engine (yours) because the CG is usually further aft than if you have a 540 up front.
If the above are sorted, then a lower speed approach can be flown with F3 or F4. Assuming normal flap rigging, the only difference is that F4 adds more drag (but doesn't change the stall speed). Having more drag enables you to carry a little more power and retain a little more elevator control. The key is to keep power on. Flap rigging can vary a bit between builders and is felt by how hard it is to pull the flap handle.
Slow initially to 50kts (60mph) while maintaining straight and level. You'll have to raise the nose to do this. It will feel like you're practicing a stall entry. Compared to an actual stall, the nose would be higher again so it's good to compare the two. When the engine cowling (prop spinner) is just touching the horizon, add just enough power to hold it there and then start a gentle descent with the spinner still touching the horizon. That's the pitch attitude to go for. You should find that the airspeed is still above the stall speed by about 1.3x. After practice you tend to stop watching airspeed and just watch the pitch attitude, but that took me many hundreds of landings. Best to do this with a competent instructor or another pilot who is well versed in STOL ops until you get the hang of it, and start at higher altitude. Do a few stalls too, so you can recognize the difference between the two. The full stall attitude with power on usually occurs at a pitch attitude above the 3-point attitude, so if you're crossing the fence and gently raising the nose, the feeling is like trying to drag the tail wheel onto the ground. That will put you right on the edge of the stall. One thing to be aware of is that at low speeds there isn't always enough energy to flare the aircraft, so in that case you need to add power to flare.
This all took me a while to learn.....baby steps......stay safe, have fun. These's a lot more BH specific info here www.bearhawkblog.com/tail-wheel-training and in the articles section. You'll also find a contact for me there if you'd like to email.
One thing to add, is when discussing speeds, there's an assumption that our speeds are all checked for position error. Usually they are not. So what I'm calling 50KIAS could show as 55KIAS on yours for example. Best to target the pitch attitude and find your aircraft's own happy place.