best glide speed

[pembquist]

I have Avfuel Deficit Disorder and can someone tell me how find best glide?  I thought it would be close to best rate of climb which I thought was the default speed when you hit alt x.  Gliding the spit 8 i thought I would cover more ground than I do.

[GNucks]

That's a good question. I have bad luck with the radiator in the Dora sometimes and have to glide most of the way home. If you've got enough altitude I would recommend just using the Shift+X autopilot with our nose just a little bit below the horizon.

[FLS]

The lift curve is kind of flat before it drops off so it's good to err on the fast side. I like to glide around 200 indicated.

[RTHolmes]

first off when gliding you should wind your rpms all the way down, reduces drag alot. I glide home alot and do it by making sure that I'm level and have as much speed as possible before the engine quits (after a WEP climb at best climb rate), then setting the descent rate to 500-1000fpm. I figure you want to be as fast as possible to start with because theres more chance of being bounced further out from your base.

does gliding all the way at best climb speed maximise the ground you cover? I'm not sure about that

[FLS]

Best climb speed is too slow. Also your max time aloft speed does not cover as much ground as best glide speed. Good point about RPMs.

[lulu]

I suggest:

1. Reduce RPM at minimum - but take care to have no roll;

2. Reduce manifold a bit - now you will suffer roll a bit;

3. Do not exceed 0 climb rate.


 

[Krusty]

I believe Pyro or Skuzzy chimed in once and said "about 10mph slower than best climb"...

Just be sure to reduce RPM like mentioned above.

[TequilaChaser]

DamnedRen ( <AH BBS username ) or Ren did some good research on this a few several years ago when he was still an AH  Trainer...if you do a search on the boards and only do an advanced search using only the Aces High Help & Training Forum and use Glide Speed and Ren you might find it.....

I'll see if I can dig it up for you this evening, if noone has found it by then.....

[Krusty]

I believe he was more interested in distance covered than least amount of descent. That's another subject altogether, and an interesting one. I personally use auto climb default while descending unless I need a bit less than the default speed (i.e. scraping the ground a the last second)

[Stoney]

I did some testing with a P-47M a while back.  What I found was that best glide speed was faster than the default alt-x speed for the Jug-M.  Prop drag can have a considerable impact on the distance you can cover while you glide.

The graph shows best glide speed with and without the prop feathered (representing an out-of-fuel condition versus engine damaged and out condition).

Aircraft was at 14,000 lbs and at 5,000 feet MSL...



For glide speed, lower is better...

I can refer to you to the testing methodology I did, but its pretty laborious.  Just off-hand for MA use, I'd take the default alt-x speed of the plane and add 10-15%.

[FLS]

Why did you use TAS instead of IAS?

[Stoney]

Don't know...I'd have to go back and look at my numbers/notes from the test.  There was a reason though.  That being said, I suppose the conversion can be done using standard conditions

[Stoney]

Why did you use TAS instead of IAS?

Looking at my notes:

I used TAS in order to determine the speed at which the most horizontal distance is covered, since ground speed (assuming no wind in AH) is = to TAS.  Looks like the IAS was 175 for the windmilling condition and 180 for the stopped condition.   

[CRYPTIC]

 Here is the write-up from Ren I had saved it awhile back.

There are 3 standard auto pilot settings in AH2. Auto Level, Auto Speed and Auto Angle. you can test
them using x, alt-x and as you said ctrl-x. One thing about the auto pilots is if your stick needs
calibration it might not hold the auto pilot you engaged.
Auto level is level flight. Self explanatory.
Auto Speed sets the climb rate in MPH. For example, a Yak will go from take off to almost 16,000 at
230 mph. Not bad if your wanting to grab while covering lots of distance, and grabbing a drink. To set
it you merely bring up the text buffer (/ key), type in .speed 230 and hit enter.
Auto Angle is a little different and you've touched on a nifty fact about it. Yes, you might point the nose
skyward and hit ctrl-x and the plane will climb until she runs out of airspeed then her nose will slowly
drop a required amount to maintain as close to the original nose up configuration as she can muster. At
that point she may be very close to the edge of a stall. If you click out of the
auto angle mode she just might fall off on you. Another nice thing is you can trim to a given speed then
hit auto angle and she'll stay there. This is helpful when you find you are just about out of gas but you
may be able to convert some altitude to distance.
Many of the planes will glide, engine off, at 120 mph in a 1,000 fpm descent. That's 2 miles for every
1000 ft of lost altitude. If you're trying to make a field that is 12 miles away and you have 7k altitude
you will glide home safely. Just trim the plane nose low to around 500 descent and hit auto angle. She
will slowly nose down to around 1k fpm descent
Another sneaky fact about fuel burns to get you home. Hit auto level and pull all the power off the
plane. Throttle back rpm and manifold. The plane will begin to slow. Eventually you will begin to there
the stall warning buzzer. Bring up your E6B and begin adding just enough power to maintain level
flight, no more. Now take a look at your E6B. You will have gone from 3 miles of gas left to 100 miles.
And you maintaining level flight! Try it. See what distance your favorite ride will give you when you
just finished a fight and looked at the ole gas gauge. You may get home with ease.
I think

[MachFly]

See This Thread: http://bbs.hitechcreations.com/smf/index.php/topic,308176.0.html (or at least the first post)