F-18F Ready for first mission
04-04-2013, 06:55 AM
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RE: F-18F Ready for first mission
ORIGINAL: Joe Westrich
Sorry if this is distracting to the thread, but I have the Y/A F-18 that will soon be finished. I have heard of the elevator blanking effect for a while now and it has made me concerned.
A friend of mine had one and had Ali do the maiden. Ali couldn't get it to rotate on the first try. My buddy had the CG on the front spar and rec throws on the elevators per the manual. After the first try, Ali had him take the 3 big weights out of the nose and said '' give me all the elev through you can''. The 2nd try was successful and flew nice. Removing the 3 weights moved the CG 11mm behind the front spar. On the next flight, my buddy flew it and everything was fine until landing. At about 12ft, it stopped its normal decent and just dropped out of the sky. He did a lot of damage, clearing all the doors and gear off of it. Now, I can't tell you if it was a stall or if the elevators lost needed airflow. I can said that Ali seemed to have a more shallow decent on his landing.
I guess what I am getting at is that I want to know what the best setup is for the Y/A airframe. Where is the best CG, where should the flaps be on landing and how much elevator throw do you use???
Also, I know the full size F-18 use flaperons on landing. I had thought if I used flaperons, I could use less center flaps which may reduce the loss of airflow over the elevators. Now I think that is a bad idea. I don't want a tip stall situation. So as of now, I think I will use about 30deg of flaps and neutral ailerons on landings. Does this sound ok??
Sorry if this is distracting to the thread, but I have the Y/A F-18 that will soon be finished. I have heard of the elevator blanking effect for a while now and it has made me concerned.
A friend of mine had one and had Ali do the maiden. Ali couldn't get it to rotate on the first try. My buddy had the CG on the front spar and rec throws on the elevators per the manual. After the first try, Ali had him take the 3 big weights out of the nose and said '' give me all the elev through you can''. The 2nd try was successful and flew nice. Removing the 3 weights moved the CG 11mm behind the front spar. On the next flight, my buddy flew it and everything was fine until landing. At about 12ft, it stopped its normal decent and just dropped out of the sky. He did a lot of damage, clearing all the doors and gear off of it. Now, I can't tell you if it was a stall or if the elevators lost needed airflow. I can said that Ali seemed to have a more shallow decent on his landing.
I guess what I am getting at is that I want to know what the best setup is for the Y/A airframe. Where is the best CG, where should the flaps be on landing and how much elevator throw do you use???
Also, I know the full size F-18 use flaperons on landing. I had thought if I used flaperons, I could use less center flaps which may reduce the loss of airflow over the elevators. Now I think that is a bad idea. I don't want a tip stall situation. So as of now, I think I will use about 30deg of flaps and neutral ailerons on landings. Does this sound ok??
What you've described is the classic F-18 stall. You get very little warning before it simply stops flying and drops like the proverbial lead ballon! At this point the only thing that will save it is increased airspeed, ie more throttle. Unfortunately most people not familiar with this characteristic will do the absolute worst thing in this situation. They haul back on the elevator, which only deepens the stall and makes it virtually impossible to recover, without a whole bunch of altitude and increased thrust! The F model, because of the larger LEX's can go deeper, ie nose high, and still recover, but if you let the C model nose come up in the stall, you're basically toast!
In answer to your questions, it sounds like the 11mm back of spar works, it's confirmed thru flight experience. Your buddy's mistake was he allowed it to get too slow on final and probably tried to hold the nose up. It's much better on the Yellow to start by landing a little fast and slowly work your way down to a slower speed as you get used to the jet. The most important thing to remember though, is that if you do find yourself having stalled the jet, the rate of descent suddenly increases, DON'T ADD UP ELEVATOR! Just punch the throttle and let it fly out. You'll only get the one chance to do it right.
David S
04-04-2013, 07:41 AM
#53
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RE: F-18F Ready for first mission
ORIGINAL: Joe Westrich
Thanks David. BTW... where is your CG set on your Y/A f18?
Also, do you do anything with your ailerons.... spoilers or flaperons?
Thanks David. BTW... where is your CG set on your Y/A f18?
Also, do you do anything with your ailerons.... spoilers or flaperons?
I'm currently building another Yellow F-18 now. I honestly don't remember where it was on the one I had, it's been several years ago, but the 11 mm back of the spar sounds about right. The jet doesn't need flaperons. The flaps are more than adequate to provide the lift needed, unless you've built a brick. And in that case, you still be better off to get rid of the extra weight and fly it as setup.
Your best bet would be to contact Sean Evans. He is a Yellow rep and has the most current info on correct setup. Mine won't be RTF till this fall.
David S
04-04-2013, 08:37 AM
#54
RE: F-18F Ready for first mission
gents, I'm intrigued by the previous posts regarding your experiences with the Hornet. bummer for sure on the loss of Randy's airframe but in the 3 hornets i've owned (1 small Ducted Fan YA 18 and 2 Large YA 18) I've never experienced the "blanking stab" phenomenon. I generally only have one flap setting, so maybe that makes a difference, and try to find a happy blend of lift / drag. for takeoff / landing generally 35-45 degrees of flap deflection....not scale I know but hey it's a model.
In full scale flying, all airplanes will let the pilot know when loss of directional control is imminent, whether it's airframe buffet or aural alert. Unfortunately for us, although technology is approaching this capability, we don't have any indication that the above is occurring except from our years of experience in deciphering what our models are doing. We have to constantly decipher the airplanes performance and this is most important in the landing pattern where rate of closure, rate of descent and throttle position have to constantly be interpreted.
All variants of the Hornet, F/A 18 A-F, are high drag airframes when compared to other modern day high performance fighters, but it's also the most stable in all flight regimes (just my opinion) This is most evident in the landing pattern where a balance of engine power (thrust) and aircraft attitude (aoa) create the easiest to land platform of all modern day fighters (marginally edged out by the F15 and Typhoon...ok ok the F16 also
)
Big D is certainly correct in stating "DO NOT ADD ELEVATOR" if you are experiencing a high rate of descent....you must ADD POWER Immediately and hope you have the thrust to fly out of the self induced stall prior to impacting the runway...
there are countless Blood Curdling videos of Landing Signals Officers on aircraft carriers telling the pilot thus because the pilot trying to land hasn't recognized the potentially dangerous situation he has allowed the aircraft to enter. We are our own Landing signals officers every time we fly because we are constantly judging our airplanes, thrust / aoa / rate of closure / descent and this is where a good buddy spotting for you can say the proverbial...."dude I think you are getting slow / fast...whew you pulled that out your *****" that might help you recognize or evaluate what your friend is saying and then adjust aircraft performance appropriately.
Ultimately (especially when flying the Hornet), a loss of elevator control "blanking stab" is a byproduct of lower than normal flying speed for the aircraft configuration. The increasing rate of descent, perhaps alarming rate of descent needs to be recognized and corrected with more power not more elevator. This condition will have been indicated by the airplane long before we recognized it on the ground.
This is where a good flying buddy or an extra set of eyeballs can help.
my .02c
happy flying season
In full scale flying, all airplanes will let the pilot know when loss of directional control is imminent, whether it's airframe buffet or aural alert. Unfortunately for us, although technology is approaching this capability, we don't have any indication that the above is occurring except from our years of experience in deciphering what our models are doing. We have to constantly decipher the airplanes performance and this is most important in the landing pattern where rate of closure, rate of descent and throttle position have to constantly be interpreted.
All variants of the Hornet, F/A 18 A-F, are high drag airframes when compared to other modern day high performance fighters, but it's also the most stable in all flight regimes (just my opinion) This is most evident in the landing pattern where a balance of engine power (thrust) and aircraft attitude (aoa) create the easiest to land platform of all modern day fighters (marginally edged out by the F15 and Typhoon...ok ok the F16 also
) Big D is certainly correct in stating "DO NOT ADD ELEVATOR" if you are experiencing a high rate of descent....you must ADD POWER Immediately and hope you have the thrust to fly out of the self induced stall prior to impacting the runway...
there are countless Blood Curdling videos of Landing Signals Officers on aircraft carriers telling the pilot thus because the pilot trying to land hasn't recognized the potentially dangerous situation he has allowed the aircraft to enter. We are our own Landing signals officers every time we fly because we are constantly judging our airplanes, thrust / aoa / rate of closure / descent and this is where a good buddy spotting for you can say the proverbial...."dude I think you are getting slow / fast...whew you pulled that out your *****" that might help you recognize or evaluate what your friend is saying and then adjust aircraft performance appropriately.
Ultimately (especially when flying the Hornet), a loss of elevator control "blanking stab" is a byproduct of lower than normal flying speed for the aircraft configuration. The increasing rate of descent, perhaps alarming rate of descent needs to be recognized and corrected with more power not more elevator. This condition will have been indicated by the airplane long before we recognized it on the ground.
This is where a good flying buddy or an extra set of eyeballs can help.
my .02c
happy flying season
04-04-2013, 10:32 AM
#55
RE: F-18F Ready for first mission
Really great explanation Buck! Here is a video of me landing my C model where I used power to manage the landing... if I only applied elevator the gear would have gone through the rails.
[youtube]http://www.youtube.com/watch?v=mwpcvi2kX14&sns=em[/youtube]
[youtube]http://www.youtube.com/watch?v=mwpcvi2kX14&sns=em[/youtube]
04-04-2013, 02:32 PM
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RE: F-18F Ready for first mission
ORIGINAL: Chris Smith
I think Randy's post needs to be repeated. '' Hit the flap switch, it pitched down''. Stall or rate of descent was not a cause if we're still talking about his model.
I think Randy's post needs to be repeated. '' Hit the flap switch, it pitched down''. Stall or rate of descent was not a cause if we're still talking about his model.
The last few posts were not made regarding Randy's occurrence. They were in answer to Joe's comments in post #47.
"At about 12ft, it stopped its normal decent and just dropped out of the sky. He did a lot of damage, clearing all the doors and gear off of it. Now, I can't tell you if it was a stall or if the elevators lost needed airflow. I can said that Ali seemed to have a more shallow decent on his landing. "
David S
04-04-2013, 04:28 PM
#60
RE: F-18F Ready for first mission
good point, and a good arm chair quarterback would say, in this case the prudent move would've been to raise the flaps immediately since it was flying fine up until they were applied and land with no flaps.
a technique I use with all my planes is to be fully configured once established on downwind. it offers a couple of benefits, higher altitude to recover and wipe the sweat off your palms or retrieve a new set of underwear, in case something goes wrong, and it allows you more time to establish a power setting that stabilizes the airplane prior to turning final.
I call it "counting the clicks" because once you know where the stabilized power setting is located, any movement "click counting" can help correct a fast "overpowered" or slow "underpowered" energy state for the given aircraft configuration.
once again bummer about the crash and my previous post was in reference to "blanking stabs with flap deployment" on all variants of Hornets.
a technique I use with all my planes is to be fully configured once established on downwind. it offers a couple of benefits, higher altitude to recover and wipe the sweat off your palms or retrieve a new set of underwear, in case something goes wrong, and it allows you more time to establish a power setting that stabilizes the airplane prior to turning final.
I call it "counting the clicks" because once you know where the stabilized power setting is located, any movement "click counting" can help correct a fast "overpowered" or slow "underpowered" energy state for the given aircraft configuration.
once again bummer about the crash and my previous post was in reference to "blanking stabs with flap deployment" on all variants of Hornets.
ORIGINAL: Chris Smith
I think Randy's post needs to be repeated. '' Hit the flap switch, it pitched down''. Stall or rate of descent was not a cause if we're still talking about his model.
I think Randy's post needs to be repeated. '' Hit the flap switch, it pitched down''. Stall or rate of descent was not a cause if we're still talking about his model.
04-04-2013, 06:34 PM
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RE: F-18F Ready for first mission
ORIGINAL: yeahbaby
good point, and a good arm chair quarterback would say, in this case the prudent move would've been to raise the flaps immediately since it was flying fine up until they were applied and land with no flaps.
a technique I use with all my planes is to be fully configured once established on downwind. it offers a couple of benefits, higher altitude to recover and wipe the sweat off your palms or retrieve a new set of underwear, in case something goes wrong, and it allows you more time to establish a power setting that stabilizes the airplane prior to turning final.
I call it ''counting the clicks'' because once you know where the stabilized power setting is located, any movement ''click counting'' can help correct a fast ''overpowered'' or slow ''underpowered'' energy state for the given aircraft configuration.
once again bummer about the crash and my previous post was in reference to ''blanking stabs with flap deployment'' on all variants of Hornets.
I agree with getting the flaps back up, remember this all happened in about 3 seconds.
I had gear down at the proper speed, I hit the flap switch,(flaps were slowed to about half speed) the plane pitched down. I expected some so I fed up elevator. This has no effect, by now the plane is pointing straight down and gaining speed. I of course get the flaps up (slowed this direction also) by now we're about 2 seconds in to this journey. As the flaps come up the plane seemed to flatten out some but I likley still had a fistfull of elevator. With the wingrock seen on the video- editted out of the youtube version- indicates a high speed stall. But it was already over anyway with terra firma closing fast.
My final theory is- the elevators disappeared, It then turned into a delta with the flaps acting as full down elevator.
If I run across anothe 7 grand, I may do another one. I will likely not use the flaps as the plane obviously doesn't like them. that would save two servos also.
My salvage list consists of 2 unscaved servos, 3 beatup but repairable servos, a couple turnbuckels, a beatup but maybe useful landing gear, 2 battery packs maybe usefull for some ground equipment, one tip missle, and 4 drop tanks- wich were not on the plane.
But I still have my health, and my L-39, and my F-15, and my Turbinator with a brand new k100g. Life ain't so bad.
Live It,
RM
good point, and a good arm chair quarterback would say, in this case the prudent move would've been to raise the flaps immediately since it was flying fine up until they were applied and land with no flaps.
a technique I use with all my planes is to be fully configured once established on downwind. it offers a couple of benefits, higher altitude to recover and wipe the sweat off your palms or retrieve a new set of underwear, in case something goes wrong, and it allows you more time to establish a power setting that stabilizes the airplane prior to turning final.
I call it ''counting the clicks'' because once you know where the stabilized power setting is located, any movement ''click counting'' can help correct a fast ''overpowered'' or slow ''underpowered'' energy state for the given aircraft configuration.
once again bummer about the crash and my previous post was in reference to ''blanking stabs with flap deployment'' on all variants of Hornets.
ORIGINAL: Chris Smith
I think Randy's post needs to be repeated. '' Hit the flap switch, it pitched down''. Stall or rate of descent was not a cause if we're still talking about his model.
I think Randy's post needs to be repeated. '' Hit the flap switch, it pitched down''. Stall or rate of descent was not a cause if we're still talking about his model.
I had gear down at the proper speed, I hit the flap switch,(flaps were slowed to about half speed) the plane pitched down. I expected some so I fed up elevator. This has no effect, by now the plane is pointing straight down and gaining speed. I of course get the flaps up (slowed this direction also) by now we're about 2 seconds in to this journey. As the flaps come up the plane seemed to flatten out some but I likley still had a fistfull of elevator. With the wingrock seen on the video- editted out of the youtube version- indicates a high speed stall. But it was already over anyway with terra firma closing fast.
My final theory is- the elevators disappeared, It then turned into a delta with the flaps acting as full down elevator.
If I run across anothe 7 grand, I may do another one. I will likely not use the flaps as the plane obviously doesn't like them. that would save two servos also.
My salvage list consists of 2 unscaved servos, 3 beatup but repairable servos, a couple turnbuckels, a beatup but maybe useful landing gear, 2 battery packs maybe usefull for some ground equipment, one tip missle, and 4 drop tanks- wich were not on the plane.
But I still have my health, and my L-39, and my F-15, and my Turbinator with a brand new k100g. Life ain't so bad.
Live It,
RM
04-04-2013, 08:33 PM
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RE: F-18F Ready for first mission
One last thought and I will let you have your peace with it. Is it at all possible that you had mistakenly programmed out your elevators with your flap switch? It sounds crazy but I have seen very experienced people overlook something like that.... It is reproducible. You just need to plug in new servos into a new Rx and see what happens. You have all your programming in your radio so you can't lose that in a crash.
04-04-2013, 08:41 PM
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RE: F-18F Ready for first mission
ORIGINAL: Joe Westrich
One last thought and I will let you have your peace with it. Is it at all possible that you had mistakenly programmed out your elevators with your flap switch? It sounds crazy but I have seen very experienced people overlook something like that.... It is reproducible. You just need to plug in new servos into a new Rx and see what happens. You have all your programming in your radio so you can't lose that in a crash.
One last thought and I will let you have your peace with it. Is it at all possible that you had mistakenly programmed out your elevators with your flap switch? It sounds crazy but I have seen very experienced people overlook something like that.... It is reproducible. You just need to plug in new servos into a new Rx and see what happens. You have all your programming in your radio so you can't lose that in a crash.
04-05-2013, 03:07 AM
#66
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RE: F-18F Ready for first mission
Did you have flaps down mix with Elevator up?
P.S If you did Disregard.
good luck with the next one amigo. the Hornet will always turn heads on the flight line.
Here are some of my landing with flaps/ elevator mix. One is at a very small RC field with lot of trees..almost like flying in a bowl.
http://www.youtube.com/watch?v=6bqbBxHGtUg
http://www.youtube.com/watch?v=PlezluCrBuM
http://www.youtube.com/watch?v=gg5bh_f_JOU
http://www.youtube.com/watch?v=KM2PcyrrSYw
04-05-2013, 04:02 AM
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RE: F-18F Ready for first mission
ORIGINAL: Randy M.
seriously??
ORIGINAL: Joe Westrich
One last thought and I will let you have your peace with it. Is it at all possible that you had mistakenly programmed out your elevators with your flap switch? It sounds crazy but I have seen very experienced people overlook something like that.... It is reproducible. You just need to plug in new servos into a new Rx and see what happens. You have all your programming in your radio so you can't lose that in a crash.
One last thought and I will let you have your peace with it. Is it at all possible that you had mistakenly programmed out your elevators with your flap switch? It sounds crazy but I have seen very experienced people overlook something like that.... It is reproducible. You just need to plug in new servos into a new Rx and see what happens. You have all your programming in your radio so you can't lose that in a crash.
