350 Power Graph Magic

[Nomex]

Helidude - you're pm'd - if he can put that astar chart on a computer program, he is a whiz

[Jammed left]

Yeah...I don't want to be that guy....but B2's always Ng out first?????????

 

the ones I fly don't always Ng out first..

 

ahhhhhhh clarity can be annoying!!!

[rainman]

I agree with Jammed left.

Mine torques out here at sea level all year long on the coast, but up in the 12000ft mountains of China the NG out waaaayyy before torquing or temping out. Still a nice performer up high but I sure needed and wanted the B3 grunt. Never flown the 407 but sounds fun and looks easier to longline out of so must be good right?

[407 Driver]

ahhhhhhh clarity can be annoying!!! You said it, One just can't risk a blanket statement and get away with it here hey !

I was referring to performance at altitude, in both 407's and B2's. The 407 generally has Q as the limiting factor all winter, and up to a certain Altitude /Temp in the summer ... just as a B2 has.

Rainman, how accurate did you find the performance charts to be up there at the top-of-the-envelope? still quite accurate? (and on the conservative side) I'd guess?

 

Skull, look what you started, or did I start this one...again?

[Nomex]

Sorry about the confusion boys - I was talking about at altitude, like 407D said....

 

You're right, you can't get away with anything here!

[rainman]

407 driver, I found that the charts were very conservative. Also the perfect zero wind conditions never exist up there. I found that the b2 would outperform the HOGE chart by up to 500lbs without exceeding the max Ng. We also had a new aerofilter instead of the sand filter. Worked like a charm for keeping the Gobi desert out but hurt the performance more. That chart said at 14000 ft and +5 C we would be able to HOGE with 30% fuel and an emty hook plus co-pilot and pilot. That's it!! Of course we would be pulling 600 Lb drills off the hill without too much trouble, barring unfavourable winds or no wind. The b3 apparently will give about 400lbs more lift that the b2 at 14000 ft. We definately needed it as our staging was at 10000 ft

[skullcap]

Well actually was splitting the difference as one Alpine engineer was telling me that Alpine doesn't accept an engine unless is a +15 which puts it up around 900 ponies. I don't know what the B3 transmission limit is either, sorry.

 

Back to the original question, do NOT pull to a max takeoff limit only maximum continous limit.

 

Canadian does power checks on BA's in 55 knt climb when the a/c has the snow protection kit or sand filter installed. Seems to make a difference to marginal engines, but I'm not sure if there is paperwork supporting the method.

 

 

sc

[jetbox]

Doesn't the flight manual for each type clearly define the flight attitude to be in while doing the power check as it greatly affects the results!!??

If you're not doing it as per the flight manual, you're doing it wrong!!!

[407 Driver]

Hey Skull, the +15 means +15 degrees C MGT above spec, not +15% power. I'm not sure what +15 C works out to on the MGT, but if the spec is 768C for that power check, and the engine only pulls 753, that equals about 2% better ?

I struggled with an engine at near 0 C for 6 months...completely legal, passed power checks ! Lifted as per performance charts too !

Thankfully, most C47's are now in the +20 or better.

[skullcap]

Well, em, well, um, um, so there.

 

They are ugly, ya, thats right and well, so there.

 

 

I have flown a few B2's around the 2750 lb mark, one am driving now is 2820. Will be mucho lighter come fall when have some time to put some lightning holes in her and get rid of some junk.

 

sc :up: