Today's Message Index:
----------------------
1. 10:49 AM - Re: Engine down thrust angle (Gary Vogt)
2. 06:18 PM - FAA Safety Seminar at AUN on Sat, 2/12 - hosted by AuCountry (cwleach)
3. 07:26 PM - Re: FAA Safety Seminar at AUN on Sat, 2/12 - hosted by AuCountry (Gary Vogt)
4. 07:28 PM - Tiger with .3 degrees up engine thrust angle (Gary Vogt)
5. 07:28 PM - Cowling update (Gary Vogt)
6. 08:03 PM - Re: FAA Safety Seminar at AUN on Sat, 2/12 - hosted by AuCountry (cwleach)
Message 1
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| Subject: | Re: Engine down thrust angle |
Hi Barry,
with all due respect, what you say does make some sense, but . . .
There is a down thrust on the elevator to keep the nose up and that is created
by the air flow. (HUH?)
- - - - In flight, the elevator is rarely in a position to raise the nose on
a plane that wants to go fast. Disregarding the drawing in "Stick and Rudder,"
if you want to go fast, the horizontal needs to be flying. I.e., the elevator
needs to be lifting the plane. Or, at a bare minimum, provide a minimum down
force. That is why the plane is faster with aft CG loading.
- - - - With a down thrust angle, less force is needed on the tail to hold
the tail down.
There is a lateral pivot point which balances down thrust of the
elevator against down thrust of the engine.
- - - - Down thrust of the engine? What are you talking about here? The
elevator down thrust, from the classical point of view, balances the lift from
the wing about the aircraft CG.
AND this is a BIG ONE - It is much easier to land a plane with down-thrust to an
engine than one with up-thrust. With up-thrust you have to fly the plane onto
the runway. SO, what happens with ZERO Thrust?
- - - - I flew the subjects plane before lowering the engine 1/2 degree. I
flew it after. I didn't notice any difference. It still has .3 degrees up
thrust angle. The plane flies fine.
- - - - In a landing configuration, there is so little thrust from the engine
compared to the aircraft angle of attack as to make it a non-issue.
- - - - I do agree that with and engine with several degrees of up angle
thrust, it would be like landing down-wind.
There is more of a neutral feel and WHICH I PREFER - And when power is cut there
is only a small pitch change.
- - - - Modelers that build free flight and remote control always build with
down thrust on the engine. There is a web site for remote control plane
builders that outlines the process for determining the optimum down thrust to
keep the plane stable during throttle changes.
- - - - With an increase in power from cruise condition, the increase in
effective angle-of-attack due to increase speed, has the effect of lifting the
nose of the plane about the CG. With a down thrust angle, the plane feels more
stable.
- - - - Likewise, with a decrease in power from a full power condition, the
plane will want to drop it's nose. With a down thrust angle, that trim has
already been trimmed in and the effect is less diversion from horizontal flight;
i.e., a more stable airplane.
With Up-Thrust when the power in cut the plane wants to DIVE - Since a lot of
down elevator is used to keep the plane S&L. So what happens with Down-Thrust?
- - - - see above. I agree.
When the power is cut the plane will start to balloon just a little... Most
people will not even notice it. And in many cases you will already be trimmed
very close to best glide SO there is less work to do when setting up for a
landing.
- - - - see above. I agree.
NOW! ALL this information is dependent on HOW MUCH thrust we are talking about.
If the feel is that noticeable you have some major thrust errors to correct.
________________________________
From: FLYaDIVE <flyadive@gmail.com>
Sent: Thu, February 10, 2011 5:06:11 PM
Subject: Re: TeamGrumman-List: Engine down thrust angle
Gary & Team:
>From my experienced down thrust is a good thing ... IN MODERATION.
There is a down thrust on the elevator to keep the nose up and that is created
by the air flow.
There is a lateral pivot point which balances down thrust of the
elevator against down thrust of the engine.
AND this is a BIG ONE - It is much easier to land a plane with down-thrust to an
engine than one with up-thrust. With up-thrust you have to fly the plane onto
the runway. SO, what happens with ZERO Thrust?
There is more of a neutral feel and WHICH I PREFER - And when power is cut there
is only a small pitch change.
With Up-Thrust when the power in cut the plane wants to DIVE - Since a lot of
down elevator is used to keep the plane S&L. So what happens with Down-Thrust?
When the power is cut the plane will start to balloon just a little... Most
people will not even notice it. And in many cases you will already be trimmed
very close to best glide SO there is less work to do when setting up for a
landing.
NOW! ALL this information is dependent on HOW MUCH thrust we are talking about.
If the feel is that noticeable you have some major thrust errors to correct.
Barry
"Chop'd Liver"
Message 2
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| Subject: | FAA Safety Seminar at AUN on Sat, 2/12 - hosted by AuCountry |
Hey, Gary, why no mention of your hosting the FAA Safety Seminar on Saturday in
Auburn? With Colin Aro as the man behind the microphone and a bevy of Grummanites
expected to descend on "Wings" restaurant for lunch, I'd have thought there'd
be more info here.
Looks like there are still a few seats open for preregistration on FAASafety.gov
but its filling fast!
[I'm committed to a seminar in Redding Saturday AM but hope to get back to AUN
before everything winds down. Gotta see those Grummans, you know!]
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=330688#330688
Message 3
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| Subject: | Re: FAA Safety Seminar at AUN on Sat, 2/12 - hosted |
by AuCountry
You're tight Corl, I neglected to mention the FAA seminar in Auburn. My bad.
There are 70 people signed up so far.
On-the-other-hand, I've had about a half dozen customers show up this week and
they all knew about it. Been a busy week.
And, getting busier.
________________________________
From: cwleach <cwleach@earthlink.net>
Sent: Fri, February 11, 2011 6:16:22 PM
Subject: TeamGrumman-List: FAA Safety Seminar at AUN on Sat, 2/12 - hosted by
AuCountry
Hey, Gary, why no mention of your hosting the FAA Safety Seminar on Saturday in
Auburn? With Colin Aro as the man behind the microphone and a bevy of
Grummanites expected to descend on "Wings" restaurant for lunch, I'd have
thought there'd be more info here.
Looks like there are still a few seats open for preregistration on FAASafety.gov
but its filling fast!
[I'm committed to a seminar in Redding Saturday AM but hope to get back to AUN
before everything winds down. Gotta see those Grummans, you know!]
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=330688#330688
Don't pick lemons.
See all the new 2007 cars at Yahoo! Autos.
http://autos.yahoo.com/new_cars.html
Message 4
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| Subject: | Tiger with .3 degrees up engine thrust angle |
With the cowling on, it still needs to come down at leas another .5 degrees.
Food fight? Enjoy some healthy debate
in the Yahoo! Answers Food & Drink Q&A.
Message 5
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For those of you who ordered the cowling, good news. Dave and two helpers are
cranking them out. Some of the delay was me wanting to make the trim lines as
near to perfect as possible.
When the cowling is installed with respect to the trim lines, the engine will
require about .25 to .30 degrees down thrust angle.
I having a one-off cowling made for my plane that will incorporate some mods for
speed and cooling. I hope.
________________________________
Message 6
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| Subject: | Re: FAA Safety Seminar at AUN on Sat, 2/12 - hosted |
by AuCountry
Don't sweat it, Gary ... I've been giving you a good promo through the email channels
at Lincoln, at the EAA 526 meeting, and other FAASafetyTeam avenues. It's
a great opportunity for many folks to meet/hear Colin and learn how awesome
Grummans are!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=330705#330705
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