G

g zero

Well Known Member
Getting ready for my first flight , plane is completed , paint , fairings , wheelpants . Should the first few flights be done with or without the pants and gear leg fairings ?
 
Congrats on getting 99.9 % :D

Gonna be a few varied opinions about the pants----------Vans instructions for my 10 was to fly without them if breaking in a new engine, which is what I did.
 
Fly without

Fly without for at least the first 8 hours

That way you can tell if you actually have a heavy wing or out of balance aircraft.

The only thing to consider is that your RPM will not get in the red due to the extra drag so don't think of any prop changes without flying with the pants on.

Congrats on the completion, it is such a great feeling to finally be there! Enjoy
 
Without, so you can inspect wheels and brakes between flights easily and so you can keep within your Phase 1 area by going a little slower.
 
I flew mine for the first time and for the 40 phase 1. All was good. Mostly because I did not have them ready for flight. I was too anxious to fly!:)
 
I have done all my initial flying with the pants on. If you're breaking in a new engine, you want as much cooling air as you can get for the cylinders - and the difference in mass flow rate between 150 and 170 knots is quite a bit. Everyone agrees to run a new engine at high power setting for break in - give the cooling it needs to prevent glazing the rings. Inspect the tires and breaks the same way you will the engine - by taking the cowl off after each early flight. It takes a little longer, but your engine break-in will be with you for years.
 
I did all mine with the pants on. I did initial taxi test with them off and that will pretty much tell you if there are any brake issues/leaks. I wanted the airplane flying all together as it would any other time, and there are areas (at least on the -4) gear that move around with ground operations, clearance from tire flexing vs. the pant cut-out ,ect. that are also validated during phase one. In fact I opened the cut-out due to some tire rubbing I wouldn't have seen otherwise. If the airplane is flying sideways and seems way out of trim, then take the pants/fairings off and isolate.
 
first flight/wheel pants

First, I respect all the previous posters' opinions (and thank them) . Here's my experience on the first flight of my RV-8. N9669D has a Lycon IO-360M1B with 10:1 pistons. Prop is a Hartzell BA CS. It runs cool on the ground. It also needs breaking in, so I'm keeping power up. It was about 26 degrees in WI for my 1st flight. Off the ground in less than 300 feet. In climb with full throttle and 2600 rpm (prop limitation) CHT's all 330 or less (on 1 & 2). After leveling off left full power in and was flirting with Vne. Decreased pwr to 25/25 and was indicating 0ver 200 mph. CHT's were 285 #1, 300 #2, 310 #3 and 315 #4, all varying slightly. At any lower power setting the CHT's were lower. It was suggested I land since 285 was felt too low. I have no wheel pants, gear leg or intersection fairings. If I had had them I don't think I could have kept the speed down and not had excess cooling. The next day we added Al dams in front of cyls 1 & 2. Temps now much better. In my particular case it was good, I think, not to have had the wheel pants and fairings on the airplane. YMMV!
 
I'm almost ready for my first flight and even though I have my pants and fairings ready and painted, I plan to fly without them for the first 10 hours or so.

My reasons are as previously stated by others, I want the drag during engine breakin and I want to see if I have any yaw or heavy wing tendencies without the fairings. I don't expect any engine cooling issues during the winter.

Once I get the plane flying true, when I install the fairings, I will know if I need to adjust them based on changes to flight characteristics.
 
General comment....

CHT's that are too low can be as detrimental as them being too high during initial flight testing, when you are trying to break in new cylinders.
In fact if the temps don't come high enough, it is nearly impossible to get them to break in properly.

In most cases, a hard climb to altitude is not needed for the first flights other than the first 60 seconds to gain some altitude for added safety margin (this is not usually long enough to cause excessively high CHT's). After that a flat climb profile can be used which in most cases will cool well enough in any temp conditions.
For these reasons my preference is to make the first flights with no gear fairings (particularly in winter temps this time of the year in the northern hemisphere). All initial flight testing at Van's is done this way.
 
I flew first flight fully dressed. It was a warm day in AZ and I justified it with better cooling, but in all honesty, I wanted a first flight video for my family, and after all that work, I wanted her looking her best.

I don't believe it is a big deal either way.

One added thought: IMO I wouldn't do any minor trim "tweaking" until the aircraft is in its final configuration.

You could end up tweaking twice on a ship that never needed any in the first place. Mine didn't.
 
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Wheelpants

Looks like I'll do the first few flights without the pants . Temperature wise it varies a lot this time of year in NE. Fla , could be frost in the am and 78 by lunch , depends on how the wind blows .
Thanks for the replies .
 
Just wondering if anyone has got a guesstimate of what speed loss I can expect if I remove the wheel pants from my RV-4? There's a lot of snow up here in Minnesota & I've been thinking about taking them off, just for the season, to keep snow out of them. (And just to see what it flies like as well)
 
Steve51B said:
Just wondering if anyone has got a guesstimate of what speed loss I can expect if I remove the wheel pants from my RV-4? There's a lot of snow up here in Minnesota & I've been thinking about taking them off, just for the season, to keep snow out of them. (And just to see what it flies like as well)
Click to expand...

On our -6, the difference between full fairings and no fairings was close to 20 knots if I recall correctly....
 
I thought the conventional wisdom was that flying without your pants on was a bad idea because the pant attach bracket will vibrate due to aeroelasticity / resonance and brackets have been known to fracture and depart the aircraft. I seem to recall some builders using different materials (CRES) and thicker gauge aluminum in an attempt to remedy this, years ago.

Any truth to this rumor?
 
Noah said:
I thought the conventional wisdom was that flying without your pants on was a bad idea because the pant attach bracket will vibrate due to aeroelasticity / resonance and brackets have been known to fracture and depart the aircraft. I seem to recall some builders using different materials (CRES) and thicker gauge aluminum in an attempt to remedy this, years ago.

Any truth to this rumor?
Click to expand...

Might be true (but can't confirm, since no one does that....) if you never put the wheel pants on, but for just 5 - 10 hours of initial testing I think it is just rumor.
 
I flew the first 15 hours or so with the wheel pants off. This was good for me to get a sense of how the plane was rigged. I had a heavy left wing. With the pants on, it was still there, so I probably have the leg fairings located straight.
The brackets were on the gear legs and they survived just fine during the sans wheel pant flights.

One thing I did notice was after the wheel pants on, my pitch attitude in level flight seemed to be slightly nose lower than without the pants on. Speed definitly increased a LOT!
 
Left them off on the 6. I could not run 25/25 with pants and keep out of the yellow and did not want to power back when it was bumpy.

One disadvantage of keeping them off - At one of my stops through the course of the process, something took a leak on my tire and wheel. At my first CI, I noticed some corrosion on the wheel. Upon further examination splitting the wheel, the corrosive fluids had made it inside.
It was easily repaired but watch our for dogs! (assuming it wasn't one of my neighbors.)
 
g zero said:
Getting ready for my first flight , plane is completed , paint , fairings , wheelpants . Should the first few flights be done with or without the pants and gear leg fairings ?
Click to expand...

I am just finishing phase 1 flight testing and did the first couple of hours without and then put them on. Didn't record the speed difference (could go back to my logs if you really want to know) but was able to fly at 70-75% power in either configuration to run in the engine with acceptable temps either way. So I think it doesn't really matter.

You should obviously have them on when you do your Vx/Vy measurement and rudder trim if needed.

Congrats!
 
Steve51B, expect at least 15knots faster with gear fairings and pants on. Some more and some less. First time I flew with all of them on, I couldn't believe how much faster I was going! For me, it was about 17knots all things constant. I say about because there are just too many variables. The gear fairings have a greater impact than the pants in my experience.
 
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