Question for Blue Foam

[MRussell]

Both the Thunderbirds and Blue angles fly around with ~40 lb. of down force on the stick.

40 lbs nose-down force on the sidestick in an F16 during aerobatic formation? Is that really how it works?

[speeddemon]

Re: Question for Blue Foam

40 lbs nose-down force on the sidestick in an F16 during aerobatic formation? Is that really how it works?

Its actually a modification that they do to prepare the plane for demonstration flying. It gives a positive feedback to the pilot and forces them to 'fly' the plane all the time, instead of relaxing and constantly trying to trim it up.

I remember that the Blues, when they flew the Phantoms, hung a lead weight on the control spring to provide the same effect.

[MRussell]

Re: Question for Blue Foam

Wow I had no idea they modify the control systems for the demo teams.

[Stevo]

Re: Question for Blue Foam

How does this 40lbs of nose down force effect the solo (can't remember which #) durring inverted flight? Just something that popped into my head.

[Race5]

Re: Question for Blue Foam

I was watching a program about the testing etc that the Blues go through during the selection process. One of the things they showed was a stick with a cable and weights attached to it. The pilot had to demonstrate that he could hold the stick in a neutral position with 40lbs of pull on it for at least 30 minutes. A similar thing has also been done in at least one F1 bird. Jon Sharp had a weighted spade on the evelator torque tube. In a positive G pull, the g-force would swing the weight in the other direction and make it harder to pull. The same thing in a negative g situation except of coures it made it harder to push. It was done to provide more feedback and make it easier to fly smooth.

[Blue Foam]

Re: Question for Blue Foam

The 40 lb figure comes from interviews conducted by Aviation Week and Space Technology and was published last summer. The T-birds use nose down trim and have a pre-set point that they fly with. The F-18 control system has some auto trim features that cannot be defeated, so the Blues fly with a spring that pulls the stick forward. The reported "neutral" force was also ~40 lb. The stick force gradient (increase in force vs. G) was not reported.

Sharp's "vertical pendulum" reported here is an interesting idea. It would specifically increase stick force gradient vs. G, but not stick force gradient vs. speed. Thinking about the pylon racing mission profile, it sounds like a good idea. Does anyone else use a system like it?

[spacegrrrl]

Re: Question for Blue Foam

Not exactly in the same category but after flying R/C for way too many years I always set my planes up to require slight back pressure. It was a trick one of the early pattern flyers taught me to make it easier to keep the plane in a groove. If you trim the plane neutral you are stuck in the area between spring tensions and it tends to make it harder to fly a steady line. For some reason even though it seems like it would work as well trimming the plane to tend to climb is extremely anoying and makes for a difficult job to keep the plane smoothly level.

Michele

[Chad Veich]

Re: Question for Blue Foam

Not exactly in the same category but after flying R/C for way too many years I always set my planes up to require slight back pressure. It was a trick one of the early pattern flyers taught me to make it easier to keep the plane in a groove. If you trim the plane neutral you are stuck in the area between spring tensions and it tends to make it harder to fly a steady line. For some reason even though it seems like it would work as well trimming the plane to tend to climb is extremely anoying and makes for a difficult job to keep the plane smoothly level.

Michele

I fly scale R/C and I also trim my models with a slight amount of down. It is far more natural to hold a slight bit of back pressure in order to maintain straight and level than it is to have to hold forward stick. This is especially noticeable down low where ground effect makes the airplane want to climb or balloon.

[First time Juke]

Re: Question for Blue Foam

I fly scale R/C and I also trim my models with a slight amount of down. It is far more natural to hold a slight bit of back pressure in order to maintain straight and level than it is to have to hold forward stick. This is especially noticeable down low where ground effect makes the airplane want to climb or balloon.

Chad V,

Me too. I once testflied a P-51D model and and it had to be pushed to be able to hold level ( trim was not enuf )...it was a pain in the neck to fly.

[Nemesis]

Re: Question for Blue Foam

Hi,
It's cool to read what people are thinking about with control systems. In the "museum piece" we did indeed have a "bob weight" that added stick force per "G". It worked really well, and have incorporated the same technology in to the NXT. And we did build the plane for all stick force all the time. We had force that required the stick to be pushed forward in level flight. What that did for us was as we zinged around each turn, at scary close to 6 G, yes 5 3/4-6 G, We found that we could actually relax a bit to go around the turns. Made it kind of like a few seconds of vacation....at 6G... This was a pleasant by product of our original intent to have a "pitch up" feature if you let go of the stick. There were no trim systems in the plane, we did it by having some angle of attack built into the "horriblezontal". So if things got ugly just let go, and the chances were very good that we'd find ourself with lots of altitude.
To date, we trimmed the NXT to fly on the course in the same manner via bungies and the like. The bungies are about to disappear as we are developing some cool trim systems to go into the "hot rod". It was to our disappointment this year that we tested the "pitch up feature" during this year of "maydays"...It worked as designed... In the big picture we think the stick force all the time really does give the plane a solid precise feel, and connects you to the plane around the course, and I think it helps to fly smoother. God knows I need all the help in that department I can get...
Cheers,
Jon
For the R/C guys, wouldn't it be cool to have some artificial stick force built in to the systems so as you pull the the millions of g's the stick would "fight back"? Knowing how fast the R/C world is moving it's probably in your hands already. If not, Futaba take an action!!!

[Wild Bill Kelso]

Re: Question for Blue Foam

For the R/C guys, wouldn't it be cool to have some artificial stick force built in to the systems so as you pull the the millions of g's the stick would "fight back"? Knowing how fast the R/C world is moving it's probably in your hands already. If not, Futaba take an action!!!

Force feedback in a R/C radio would be awesome. Might have prevented my SU-31 from going in yesterday.

[Apteryx]

Re: Question for Blue Foam

Jon, For the R/C guys, wouldn't it be cool to have some artificial stick force built in to the systems so as you pull the the millions of g's the stick would "fight back"? Knowing how fast the R/C world is moving it's probably in your hands already. If not, Futaba take an action!!!

Jon, if anybody could do it.. got some spare time?

Oh yeah, is Hot Glass going to happen again? Sorry I missed the last one.

Paul

[First time Juke]

Re: Question for Blue Foam

For the R/C guys, wouldn't it be cool to have some artificial stick force built in to the systems so as you pull the the millions of g's the stick would "fight back"? Knowing how fast the R/C world is moving it's probably in your hands already. If not, Futaba take an action!!!

Yes Jon,

Also the flight simulator freaks could use it. Then they could get exercise when flying several hours per day.

I have besides building Mustang models flown few of my designed Me 109 models. I read from an aviation book about testpilots comments of the initial batch of 109s finns received during WW II from Germany. The test pilot assumed that stickforces were made intentionally heavy for the pitch to avoid G-stall ( = high speed stall ? ).

I later discovered when flying a model that if one bluntly in a R/C model pulls back the stick at high speed the plane actually keeps flying into the initial direction, but does a violent 1,5 rolls/spins opposite to the propeller rotation direction. Very nasty for a pilot if that happened. The wing stalls so fast that one can't even say A. I had a long quarrel about this phenomena on an other site.

I also read about one FAF pilot experiencing it when encountering a LA-5 over the Baltic Sea during WW II. He is the sole person who has lived to tell it as far as I know. He got unconciousness at altitude and gained back conciousness just early enuf at sealevel to recover...and shot down the LA-5 when climbing back to the dogfight scene he missed ( but that is another story ).

Juke

[AAFO_WSagar]

Re: Question for Blue Foam

I've never flown an RC model but the two stick thing always seemed really counter intuitive..

What would be REALLY cool would be some sort of incorporation of the current "HOTAS" flight sim control systems for RC!

As Juke said, you could "practice" on your PC and it would also seem that RC flying would then actually help with real flying as sim time does now.

I'm sure it could be done but man, I'd bet it'd cost a bundle but with some of the models going for the prices they currently do, it'd sure be something that some guys would pony up for.

[spacegrrrl]

Re: Question for Blue Foam

Having flown several modes of two stick, several variations of single stick and even a seat with a control stick and rudder pedals I can say that after a while it can all feel natural. In the long run I've settled on mode 2 single stick because it seems to be the most common and therefore the easiest mode radio equiipment to aquire. The only configuration I never could master was reed radios that used seperate momentary contact switches on the transmitter for each control. You wouldn't believe what someone could do that mastered that! Thank goodness that they were all but gone when I started flying R/C!

Michele