350 Power Graph Magic

[407 Driver]

Nomex, I respond to your question (Re 407 Temp limited) with another question, when does a B2 become Ng limited at altitude and temp? 😀 We all get focused on Torque, who says that it has to be the defining limit, is it not acceptable to be Ng limited, or Temp limited?
I've seen a huge range of C47 engines out there. Some are great, others :down: are not. In our 7 C-47's, we have about 4 "great's" a couple of average ones, and 2 dogs. I've been told that Standard (or Acro or ?) can do a much better job of building a good engine if they have all the components Vs ..just a turbine?

The question should be...does the aircraft perform to the manufacturers published data? They all do !

I haven't seen the article from Vertical yet, it was shot in the Canmore area, so I doubt that our covert little western-slope operation is featured 🙁

Re: the B2's MGB limits, so what you're saying is that the B2 and 407 are quite close in available power? The 407 with a few % edge.

 

[Jammed left]

Back to the original question.....sorry!!!

Hey leaner...I'm not sure which model of Astar you are using, but I believe ( and I'm sure that I will be corrected if I speak in error) you need to reach an operating limit to get an accurate power check

"set engine speed to the maximum compatible with the mechanical limitation. (TQ or Ng). The bleed valve flag should not be visable in these conditions"..out of the flight manual

I know a couple of instances where not pulling to a limit has caused some moments of confusion.

Good luck

 

[Nomex]

Morning 407D - No, I'm not starting an astar/bell war here, only trying to learn a bit more. Just a question as it was actually one of your drivers that lamented about the temping out of the 407 (maybe it was one of those dogs you referred to on the other side of the mountains) - and as I haven't flown one, was curious about when temps get high and combined with altitude if there is a significant performance deterioration from what is in the AFM charts. The HOGE for the 407 is according to Bell 9650ft at 4500 lbs and +20. From your post it appears as if you can attain that figure without T4 difficulty?

Yes, its well known the B2's NG limit out first, the AFM gives the best correlation for T4 & NG:

-if T4 indicator fails, follow NG limits
-if NG fails, Max T4 750c above 15c OAT and 730c below 15c OAT
(Max Cont is 795c, so you are looking at 45-65c less than Max Cont T4 to remain within NG limits)

And yes, I guess according to your 407 figures about 19hp different in MGB limits -it appears as if the 407 can pull MCP right up to the MGB rating whereas the B2's engine is permitted to pull only within 30HP of its MGB rating.

What is the usual Empty weight for the 407 by the way (without your wallet) - 2600-2700?

Sorry to have strayed off-topic here, and going back to the Power Graph, does anyone know if there is a computer program available to chart astar power checks, similar to the one, I believe Acro has for the Bell/Augusta products. Even with a power chart as simple as the Bells, a dull pencil can easily make the difference between a + or - engine.

 

[407 Driver]

You're going to have to try and stay on topic Nomex, after all ..here at Caaviation we ALWAYS stay on topic 😀 😀 😀

The 407 airframe tends to weigh in at approx 2900, plus another 80 lbs for the basket (always attached !) Similar to the 350 performance graphs, I have found the 407 graphs to be accurate, regardless of Ng limitations or MGT (TOT) limitations.

Our (ex) 350B2's also weighed in at around 2900 lbs, given one squirrel cheek, a sliding door, and dual LF seat provisions. I've heard of B2's down to 2700 but never have seen one?

 

[helidude]

Gentlemen, I have what you've all been looking for!!!
There's a computer engineer in Montreal who happens to be Denis Robitaille's brother (for those of you who don't know Denis, he was the long time D.O.M. with Abitibi Helicopters in La Sarre and is now working for Eurocopter in Fort Erie).
Anyway, this guy's name is Paul Andre Robitaille and he sold me a program that calculates power checks on JetRangers and AS350D. This program takes into acount snow baffles, particle seperators etc. Very slick!!!
All I had to do was send him a copy of whatever powercheck charts I wanted and he converted each chart into computer lingo and voila! Instant power check!!!

If any of you are familiar with the Standard Aero power check program, his are almost identical except they are more user friendly. ( apparently, he didn't have a copyright for his program and S.A. copied it, put their name on it and went to town)

Like I said, he can make the program work for any type of engine provided he has a current copy of the flight manual power check chart.

Anybody interested can P.M. me for his number.

 

[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 :blink:

 

[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