Best rate-of-climb speed

[HydroCub]

What was the difference between piston engine and jets re this topic???

Timely thread as Im in the process of dusting off the books for an interview. I just get distracted by this web site which is a lot more interesting.
I hope you have the answer you sort King Brown.

Vx doesn't exist in the "jet" world as such..... although you could argue Vxse is a calculated factor. Jets chart performance for "obstacle climb" which starts at brake release and assumes an engine loss at V1 during the takeoff roll. It assumes a 35' obsgtacle at the end of the runway or a higher obstacle during a portion of a required departure climb. They also chart "approach climb" which starts at your missed approach point with an inop engine and requires a certain angle of climb to be maintained...or an existing obstacle cleared if it exists.

[bob turner]

and requires a certain angle of climb

Which is by definition Vx? The problem with jets is the difference between flaps extended and flaps up is often almost a hundred knots, and it is better for close in obstacles to keep the flaps set, rather than waste energy accelerating to flaps up speed. In almost all cases except short runway you can carry more weight with less flaps. But once the flaps are set, you leave them set for what are defined as close-in obstacles. Rate of climb is better when clean.

[NimpoCub]

If you want to do the Super Cub full flaps Vx climb, you will be climbing relatively slowly at an incredible angle and pretty much zero indicated airspeed. It is impressive for three reasons:

Bob, I'll not be trying to impress anyone. That's not my style. I'm not looking for this info (and then experience) so I can say "Hey guys, watch this". I want to know what's possible, I want to know how to DO IT to get out'a that short place I shouldn't be in, if I should ever get there.

I'm guessing Piper actually flight tested the Super Cub before they put that recommendation for full flaps and 45 mph indicated for best angle of climb
Is that dangerous? That's relative. I find it interesting that so many folks are so worried about their engine quitting on takeoff,

Thanks.

Oh, and I'm sorry (feel guilty?) about the thread creep, I just thought I'd get an answer, not a whole 'nuther conversation.
But, not so guilty... that I feel thanks for the comments!

[bob turner]

Nimpo - the way I do it is to set full flaps, pull the stick back into my lap, add full power, and only release the back pressure when I lose my nerve - that is, when the deck angle is looking kinda ridiculous. I do not do it often, but the climb angle is something to see, especially with a light 160 Borer. You certainly want to practice when nobody is looking, because an observer who is a pilot will think you are nuts. Do not expect to see much on the airspeed indicator.

Life is short enough anyway. I recommend not going in to places that need this technique.

[nanook]

another problem with the steep(hanging it on the prop) climb out... Piper did it with header tanks, you have to be almost vertical to lose head pressure on the forward header...something to think about if you took your header tanks out

[U-7]

A few weeks ago I made a "Time to Climb" test for another plane of mine and thought that I would do the same for my SuperCub, after reading this thread. Making this was un scientific and, of course, there are many variables. This was the best of about ten tries. Anyway, it was fun doing and I would like to try again when the air gets cooler.. Perhaps some of you would like to try. http://youtu.be/Xl3a7iYyrWk

Alex D

[King Brown]

nanook, the standard is so easy to meet, I raised flaps after take-off and climbed full-throttle at 65mph.

[U-7]

Yesterday was sunny and clear and the crosswind died down in the late afternoon. I redid a "Time to Climb". I took out all extra " Baggage" and had about 10 gal of gas on board. Used the Raising the flaps just after takeoff and climb , with full power, at 65 mph, I was able to get a time of 2 min 58 sec to 1000 meters. If interested in seeing I posted http://youtu.be/tLOoNwmt00c


Alex D

[aviationinfo]

Hi Alex, thanks for the videos. I wonder, what are the specifics of your plane, ie, empty weight/horsepower/prop?

Looks like your altimeter is calibrated in feet with a Mb window. So, where are you located---your location says NJ but to most of us here that means New Jersey...?

Andrew

[U-7]

Andrew,

My Cub has a 160hp eng with 82-42 prop andhas a empty wt of about 1120 lbs. It does have std length DC slotted wings. Idon't know if that made a difference with the rate of climb. I use 1000 meters, which is very close to 3280ft, because it's universal / international length. All of this is un- scientific and was justdone for fun. I live in the north west part of New Jersey. If youlike to see, I made a air to air video of my Cub which also shows the area ofNJ that I live. http://youtu.be/BlfigetIfgY

Thank you

Alex D

[aviationinfo]

Thanks Alex, nice plane and video. My PA-12 came from NJ and the previous owner had it based at Sky Manor.

I like to compare performance because im constantly trying to decide if i want to buy a Borer Prop. My plane weighs a bit more and has the Sensenich cruise prop, so i think I'd expect a couple hundred fpm increase in the climb. Sounds like your weight is very typical. Agreed, not sure that the slot helps the rate of climb, I think it's more for low speed work and short takeoffs. Cool!

Andrew