What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Borrowing the Horse

Ironflight

Ironflight

VAF Moderator / Line Boy
Mentor
A funny thing happened when I entered the RV world?.people started throwing me the keys to their airplanes, and telling to take them out for a spin! Now I have flown a lot of different airplanes ? anyone who has been around airports for 30+ years has bounced around in a lot of rental aircraft?.and those of us who were hangar rats and always underfoot at the local FBO when we were young have grabbed our share of stick time when airplanes were going up for a few minutes of checkout and the like. I?ve also had the chance to fly a lot of interesting simulations in my job ? from ?normal? to weird ? things with wings, and things with rockets. I?m not a test pilot, but I have been trained as a test engineer, and have had a lot of fun and a rewarding career testing some mighty high and fast flying machines. But most of that has been done sitting at a console bolted firmly to the earth?.

So here I find myself in the RV world, going to fly-ins, hanging around builds, and people say ?hey, Paul, want to take my RV up and tell me what you think? Or ?sure, take my RV for a week ? you need a way home, I have another airplane to fly ? I won?t miss it?.? Borrowing another kid?s bike? Oh sure, that was normal. Taking a neighbors boat to go do some fishing, or drag a snag out of the channel? Yeah, no big deal! But putting your hands on someone?s homebuilt pride and joy ? something they have put thousands of hours of their life into bringing to life? Wow- that is not something I take lightly!

This weekend, Jay Pratt asked if I wanted to fly the latest ?Borrowed Horse? ? his brand new, 60-hour RV-8. It?s still waiting on paint, and Jay is still working on the glass, but it?s been flying a lot, and I am afraid that I have a serious problem turning down an offer of a little stick time ? my one real weakness. Jay said ?take it up whenever you want!?, and when he looked up, I was strapping in?.A quick checkout on cockpit controls, and I was on the way. And you know what? It flew just like an RV-8! Only?.through some sort of magic which Danny King and I still don?t understand, Jay has made it lighter in roll than either my Valkyrie or Danny?s Beautiful Doll. Pitch is about the same ? heavier than some of the other RV models, but fine. Roll in most -8?s (from what I can tell) is a bit heavier ? it certainly is noticeable when I fly a -6 ? those airplanes seem to roll with no effort at all, while the Val takes a little bit of pressure ? much less than any spam can I?ve ever flow, but still, more than other two-place RV?s. Borrowed Horse feels like a -6 in roll. I have no idea why, and neither does Jay ? I?m wondering if the fact that I have a squeezed aileron makes a difference.

For the first time in an -8, I experienced the canopy buzz that I have heard about. Jay has yet to finish the skirt to the point where he?d put any seal or padding where it touches the fuselage, and I had some felt on the Val?s skirt the first time I flew it (based on other people?s inputs. I didn?t find it too bothersome ? but noticeable. I?m glad I finally know what folks are talking about! It only happens at certain speeds and angles of attack ? you can actually use it as a cue during maneuvers. I flew a couple of loops, some rolls of different types in both directions, and a few other things ? a nice, honest airplane, as all the RV?s prove to be. A very enjoyable end to a nice day up at Petit Jean State Park!

Thanks again to Jay for the trust you showed in letting me take your new child out for a walk. I guess that since I brought Shooter back without a scratch, you must have figured it was even money I could do the same thing with a model I have 600 hours flying?.:rolleyes:

I know what it's like to watch someone else fly off in your machine - I saw Danny fly off in the Val when I needed it ferried somewhere when I couldn't go. It's great to have friends that I can trust with something so important, and I am grateful that there are people that trust me as well.

Paul
 
Paul, I had the same thing happen when I bought my SNJ 25 years ago. When people see you flying a hot piece of iron they think you are a real stick and start offering to let you fly their airplanes. I became a type hunter and now have over 100 and haven't bent one yet. I really enjoy flying all kinds of airplanes but homebuilts and antiques are my favorite. Don
 
Ironflight said:
And you know what? It flew just like an RV-8! Only?.through some sort of magic which Danny King and I still don?t understand, Jay has made it lighter in roll than either my Valkyrie or Danny?s Beautiful Doll. Pitch is about the same ? heavier than some of the other RV models, but fine. Roll in most -8?s (from what I can tell) is a bit heavier ? it certainly is noticeable when I fly a -6 ? those airplanes seem to roll with no effort at all, while the Val takes a little bit of pressure ? much less than any spam can I?ve ever flow, but still, more than other two-place RV?s. Borrowed Horse feels like a -6 in roll. I have no idea why, and neither does Jay ? I?m wondering if the fact that I have a squeezed aileron makes a difference.
Click to expand...
My first guess would be differences in aileron trailing edge radius. Compare yours against Borrowed Horse.

Or, Darrol Stinton, in Flying Qualities and Flight Testing of the Aeroplane (Amazon), claims that if Frise ailerons are rigged a bit upwards from neutral, that the stick force for small deflections is reduced. Conversely, if they are rigged with the trailing edges a bit lower, the stick force for small deflections is increased. People usually rig the ailerons to match the wing tips. But the wing tips have changed over the years, and maybe that has resulted in differences in how the ailerons are rigged.

Or, perhaps there is some small difference in vertical location of the aileron at the hinge line.

Or, maybe there is a difference in the contour of the upper wing skin just before the aileron.
 
Stick in the mud.

I don't want to be a stick in the mud but I would like to know how you guys deal with the insurance issue??
I have a -6 and two close friends with -6's and we hand off the PIC while we are both in the airplanes.
It is my understanding that experimental insurance policys only cover "listed or named" pilots. So if I just hand my keys to my buddy and tell him to take my -6 for a spin and he actually does.......then the ride is completely without insurance.
Do you guys know this and accept the risk?
or do you think you are covered because the other pilot has the same type plane?
or are you just accepting the risk?
or......do you know something I don't.....???
Please enlighten me if you do....
Thanks
 
Borrowing the Cub

yakdriver said:
When people see you flying a hot piece of iron they think you are a real stick and start offering to let you fly their airplanes.
Click to expand...

My hanger mate just got a PA-11 to fly a couple weeks ago. He let me fly it this weekend. I guess if I can fly an RV I should be able to fly a Cub. (Of coarse I got 250 hours in tailwheels with my Cessna 140.) Not quite the high performance machine but fun never the less to fly.
 
Risk?

Bob,

I have a new airplane and am happy to get some input as to how other pilots think my new ride flies.

I never thought about any risk. We are having fun.
 
Bob Martin said:
snip...Do you guys know this and accept the risk?...snip
Click to expand...

I certainly understand where you're coming from, Bob. In my case, I loaned Paul my RV-6 for a week while his -8 was in the paint shop (he even wrote a nice travel story with it). Although we didn't sign any legal agreement, I know Paul would let me have his -8 until he could replace it. Knowing Jay, I'm certain he feels the same.

b,
dr
 
Last edited:
Yo Iron!

In my very limited experience with the -8, I've also noticed the roll difference you talk about as compared with the -6.

I think it's a performance vs. flying qualities issue. Performance being how fast does the aircraft roll, in degrees per second, at a given airspeed and stick displacement. Flying qualities being, how much force does it take, measured in pounds, to displace the stick a given amount at a given airspeed.

My opinion, based on zero quantified data, is the -8 has a higher roll rate, and the -6 has lighter control forces in roll.

To put it in agricultural terms: the -8 will roll faster than the -6, but you gotta shove harder on the stick to do it.

And I might add that this is all nit-picking, both airplanes fly "great," another agricultural term.

I was never a test pilot either, we need Mercedes to chime in here...
 
Bob Martin said:
I don't want to be a stick in the mud but I would like to know how you guys deal with the insurance issue??
I have a -6 and two close friends with -6's and we hand off the PIC while we are both in the airplanes.
It is my understanding that experimental insurance policys only cover "listed or named" pilots. So if I just hand my keys to my buddy and tell him to take my -6 for a spin and he actually does.......then the ride is completely without insurance.
Do you guys know this and accept the risk?
or do you think you are covered because the other pilot has the same type plane?
or are you just accepting the risk?
or......do you know something I don't.....???
Please enlighten me if you do....
Thanks
Click to expand...

I just accept the risk. 30 years ago most airplanes (even my SNJ) had open policies. Now it has changed to named pilot only in most cases. If you never take any risks in this life you don't really live. To be sure you have to weigh the the risk and if you are willing to accept the consequences. Don
 
Insurance

Jaypratt said:
Bob, I never thought about any risk. We are having fun.
Click to expand...

DeltaRomeo said:
I know Paul would let me have his -8 until he could replace it. Knowing Jay, I'm certain he feels the same. b, dr
Click to expand...

Not trying to hijack Pauls thread, and thanks for the replys.
FYI, the certified world does allow people who are quaified or rated properly to borrow planes and still be insured. It's the EXPERIMENTAL world that is different.
Also, I can add pilots to my policy (RV-6)by giving my insurance the same info on them as I give them for my insurance, ie: hours, bfr, medical, etc.
and if the added pilot is more qualified that I am, it doesn't add any additional costs to my policy, only the minor PIA of filling in the paperwork. But at least that way, we all are covered.
Play safe out there and know the risks.
Regards,
 
Kevin Horton said:
My first guess would be differences in aileron trailing edge radius. Compare yours against Borrowed Horse.

Kevin, could you expound a bit on fat radius vs thin radius.In order to get the transition from the surface to the radius as close to the edge as I could the radius seems to be a little thinner, thinner than the radius of the flaps.
I've wondered about what the effect would be if any.
Click to expand...
 
DeltaRomeo said:
I certainly understand where you're coming from, Bob. In my case, I loaned Paul my RV-6 for a week while his -8 was in the paint shop (he even wrote a nice travel story with it). Although we didn't sign any legal agreement, I know Paul would let me have his -8 until he could replace it. Knowing Jay, I'm certain he feels the same.

b,
dr
Click to expand...

But.........if there is a terrible accident, who is liable for damages or loss of life, either in the plane or on the ground? I really hate to bring up this kind of stuff but with our legal climate, anyone with assets might consider these things.

A friend of mine was out of action for many months due to injuries and I was asked to fly his nice RV-4 for him while he was unable to get in the plane. It only took a phone call to get me added to his policy.
 
Last edited:
Roll Response

I should have thought to measure roll rate Scorch - that could be part of it - also, stick length might have something to do with it - the -6's I've flown have generally had longer sticks, and therefore a bit more leverage....but then, I think that Borrowed Horse's stick length is the same as what is in the Val and the Doll, so that doesn't explain both Danny and my feeling that the forces are lighter in Jay's plane. I tend to thin kit has something to do with aileron trailing edges, but that is purely a guess. Maybe we'll have to do more research....and that means more flying!:D

AS to the insurance question, yes, that is a bit off topic for this thread - you are free to start one of your own - but I simply feel that flying an airplane offered by a friend that is essentially the same as one I have 600 hours in is an incredibly low (and to me) acceptable risk. I try not to let my life be governed by artificial constraints. I have many like-minded friends who enjoy a little freedom as well. This attitude is not for everyone, and completely wrong for many. Everyone's situation is different.

Paul
 
billdianne said:
Kevin Horton said:
My first guess would be differences in aileron trailing edge radius. Compare yours against Borrowed Horse.

Kevin, could you expound a bit on fat radius vs thin radius.In order to get the transition from the surface to the radius as close to the edge as I could the radius seems to be a little thinner, thinner than the radius of the flaps.
I've wondered about what the effect would be if any.
Click to expand...
Apparently, a smaller trailing edge radius will increase the stick forces required for small deflections. I have seen this reported in several places, so it is probably true. I won't claim to completely understand exactly what is going on though. The only theory I can come up with is that if the radius is big enough there is a bit of a Coanda effect going on. The Coanda effect describes a condition where a flowing fluid will tend to follow a convex curve (i.e. a curve that goes away from it). Imagine a control surface that is deflected upwards. If the trailing edge radius is very sharp, the air that is flowing along the surface continues on in the same direction it was going when it passes by the trailing edge. If the radius is large, the air tends to follow along the curved radius for a while, and it leaves the trailing edge going in a bit of a different direction than it was going when it reached the radius. It takes a force to cause the air to change direction like that, and every force has an equal and opposite reaction. In the case where our control surface is deflected upwards, the air is deflected downwards a bit as it tries to follow the trailing edge radius, which requires a downward force to be applied to the air (by deflected downwards, I mean that the direction of the airflow is downwards from where it would have been if the trailing edge radius was zero). The reaction to that force is an upward force on the trailing edge, which reduces the control force required to displace the surface.

If we reduce the control surface radius, the air has to turn a sharper corner to stay attached to the trailing edge radius. It is harder to stay attached to this tighter radius, so the air doesn't get deflected though as high an angle before it separates from the trailing edge.

Obvious question - the air is flowing along both sides of the surface. Why don't the effects from the air flowing on one side balance out the effects from the air flowing along the other side? My theory is that the higher air pressure on the side that the surface is deflected to helps the air on that side stay attached to the radius, so the air coming from that side of the surface overpowers the lower pressure air coming from the other side.

This would be a lot easier to explain if you could see my hands moving :)

The above explanation is only a theory - it may or may not be correct.
Click to expand...
 
Yes Paul, more flying.

The Borrowed Horse's flaps retract a couple of degrees up past neutral.
Do not know if this could make any difference In roll rate. I built this in knowing Mauls have more speed when their flaps are up a little extra.
 
You must log in or register to reply here.
Back
Top