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  #31  
Old 12-27-2018, 02:55 PM
andrewtac andrewtac is offline
 
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Location: Friendswood TX
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Quote:
Originally Posted by YellerDaisy View Post
Apologies Bill, I was terribly vague. I was attempting to say that attempts to manually note height and position (using instrumentation and outside visual clues) was too slow/inaccurate. All required far too much attention from this pilot when workload is high and things are happening quickly (wheels up to 50' is 3-4 seconds).

I was really looking for pointers on how a 'common guy' can gather this data with reasonable accuracy (and, hopefully, without investing thousands of dollars). You have clued me into using the GPS track/recording functionality. I can see how this would work quite well. While no longer a pressing issue for me, I will still explore this as I'm a bit of a data junkie. Thank you!!

While not quite as accurate as instrumentation a good flight test engineer could probably get you something reasonably accurate. They did it before orange wire and high speed data. Ive seen some rather accurate data gathered this way.
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  #32  
Old 04-09-2019, 05:01 PM
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New to RV-8 here and I live on a grass runway airport. On take off I like to bring in power slowly as I roll forward (between 3-5 seconds to full power) to protect the prop and then I raise the tail as soon as possible to protect it from anything flying up and the runway bumps.

To those of you with more experience in the RV-8, does flap setting help to raise the tail any sooner?
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RV-8 N52VM : Dynon D-180, GTX327, SL40, Garmin 496 GPS, AP74 Autopilot, Titan 0-360A1A2N, Nickel Coated Cylinders, 2 Slick mags (both impulse coupled), engine preheater, Hartzell Plane-Power alternator, Hartzell HC-C2YR-1BFP constant speed, blended airfoil

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  #33  
Old 04-09-2019, 07:21 PM
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Thanks Nige for sharing your research. great info and write up.
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  #34  
Old 04-10-2019, 05:09 AM
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Quote:
Originally Posted by Pilot135pd View Post
New to RV-8 here and I live on a grass runway airport. On take off I like to bring in power slowly as I roll forward (between 3-5 seconds to full power) to protect the prop and then I raise the tail as soon as possible to protect it from anything flying up and the runway bumps.

To those of you with more experience in the RV-8, does flap setting help to raise the tail any sooner?
Lifting the tail is all about airflow ofer the tail and being deflected off the downward deflection of the elevator, flap won't have any effect. Another effect is the CG. Tail heavy means the elevator deflection won't be as effective at slower speeds. Generally the RV8 with 180+ gee gee's up front and CS prop gets its tail up very quickly anyway
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  #35  
Old 04-10-2019, 07:11 AM
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Low Pass Low Pass is offline
 
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Originally Posted by Pilot135pd View Post
New to RV-8 here and I live on a grass runway airport. On take off I like to bring in power slowly as I roll forward (between 3-5 seconds to full power) to protect the prop and then I raise the tail as soon as possible to protect it from anything flying up and the runway bumps.

To those of you with more experience in the RV-8, does flap setting help to raise the tail any sooner?
Yes. (extra characters)
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  #36  
Old 04-10-2019, 09:44 AM
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Quote:
Originally Posted by Pilot135pd View Post
...To those of you with more experience in the RV-8, does flap setting help to raise the tail any sooner?
Awesome, two completely different opinions about the same thing in less than 2 hours .


Quote:
Originally Posted by Capt View Post
Lifting the tail is all about airflow over the tail and being deflected off the downward deflection of the elevator, flap won't have any effect....
Sounds reasonable.

Quote:
Originally Posted by Low Pass View Post
Yes. (extra characters)
Could you give more detail as to why?
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RV-8 N52VM : Dynon D-180, GTX327, SL40, Garmin 496 GPS, AP74 Autopilot, Titan 0-360A1A2N, Nickel Coated Cylinders, 2 Slick mags (both impulse coupled), engine preheater, Hartzell Plane-Power alternator, Hartzell HC-C2YR-1BFP constant speed, blended airfoil

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  #37  
Old 04-10-2019, 09:56 AM
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Prop blast onto lowered flaps will definitely contribute to raising the tail.
I have investigated more than 1 incidents where props got into the ground because of running up to full power with flaps down and brakes locked; even though the elevator was held full up.
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Specializing in Amateur-Built and Light-Sport Aircraft
<rvmel(at)icloud.com>
North Texas (8TA5)
RV-6 Flying since 1993, 172hp O-320, 3-Blade Catto (since 2003)Sold
Legend Cub purchased 12/2017
FRIEND of the RV-1
Eagle's Nest Mentor
Recipient of Wright Brothers "Master Pilot" Award

Last edited by Mel : 04-10-2019 at 10:19 AM.
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  #38  
Old 04-10-2019, 10:11 AM
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Originally Posted by Pilot135pd View Post
Could you give more detail as to why?
Not going to get into the depths of the fluid dynamics, but lowering the flaps will make it easier to raise the tail of the -8. Both with power and without (e.g., rolling out after landing).

But back to your point of protecting the airplane, I operate off these types of strips often. At home and traveling. I too am concerned about impact damage to the prop, the bottom of the elevator and the bottom of the flaps. To minimize this, I use moderate flaps and a tail low attitude to takeoff. I use moderate stick pressure to allow the tail to float off the ground a little for the tail low attitude. Go back to the original discussion in this thread. Nigel talks about this as the fastest way to get the (-8) off the ground. And getting it off the ground stops the main wheels from throwing up debris.
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Last edited by Low Pass : 04-10-2019 at 10:17 AM.
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  #39  
Old 04-10-2019, 10:19 AM
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Quote:
Originally Posted by Mel View Post
Prop blast onto lowered flaps will definitely contribute to raising the tail.
I have investigated more than 1 incidents where props got into the ground because of running up with flaps down; even though the elevator was held full up.
Thanks Mel. So in my case since I live on a 2500' grass runway, the only reason I lift the tail quickly on take off is to protect it from anything flying up and hitting it. If I were to add 10 flaps on ALL of my takeoffs on my Before Take Off checklist, would it help get that tail in the air quicker, or would 10 flaps just be negligible and as I get used to that adding to the possibility of something worse by forgetting to raise flaps before passing 100mph or something now hitting the lowered flaps? I try to keep things as simple as possible but if it'll help I'll add it.
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RV-8 N52VM : Dynon D-180, GTX327, SL40, Garmin 496 GPS, AP74 Autopilot, Titan 0-360A1A2N, Nickel Coated Cylinders, 2 Slick mags (both impulse coupled), engine preheater, Hartzell Plane-Power alternator, Hartzell HC-C2YR-1BFP constant speed, blended airfoil

Exempt by 3 out of the 10 ways but I still donated.

Last edited by Pilot135pd : 04-10-2019 at 10:22 AM.
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  #40  
Old 04-10-2019, 10:29 AM
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Mel Mel is offline
 
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Quote:
Originally Posted by Pilot135pd View Post
Thanks Mel. So in my case since I live on a 2500' grass runway, the only reason I lift the tail quickly on take off is to protect it from anything flying up and hitting it. If I were to add 10 flaps on ALL of my takeoffs on my Before Take Off checklist, would it help get that tail in the air quicker, or would 10 flaps just be negligible and as I get used to that adding to the possibility of something worse by forgetting to raise flaps before passing 100mph or something now hitting the lowered flaps? I try to keep things as simple as possible but if it'll help I'll add it.
Optimum take-off flaps is in the neighborhood of 15. This is why differential ailerons usually have 15 of down travel. Optimum compromise between lift and drag. If you have electric flaps, try pushing the stick to one side and align flaps with the "down" aileron. Try it. I think you will like it.
__________________
Mel Asberry..DAR since last century
A&P/EAA (LifeTime) Tech Counselor/Flight Advisor/Nat'l Test Pilot School
Specializing in Amateur-Built and Light-Sport Aircraft
<rvmel(at)icloud.com>
North Texas (8TA5)
RV-6 Flying since 1993, 172hp O-320, 3-Blade Catto (since 2003)Sold
Legend Cub purchased 12/2017
FRIEND of the RV-1
Eagle's Nest Mentor
Recipient of Wright Brothers "Master Pilot" Award
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