david.perl said:
should the wheel spats be on or off for the test flight?

Thanks

David Perl
Click to expand...


There are a couple of schools of thought on this. I left mine off, then put them on later with the idea being that any trim difference attributable to the wheel pants and gear leg fairings could be isolated and identified more easily.

Also, "the" test flight? As in the only one? ;)
 
david.perl said:
should the wheel spats be on or off for the test flight?

Thanks

David Perl
Click to expand...

Off is better. Will help determining rigging and flight tracking before and after spats. Also off helps with engine break-in if you need it and allows for higher power settings and lower speeds.
Higher RV time experience also can determine this. Newbees routinely find themselves getting away from the airport with the speed and distractions. This also lends itself to spats off.
 
thanks for the rapid responses chaps. Its a new engine so engine needs breaking in and will be experienced test pilot used to flying at commercial jet speeds.
 
OK, I'll jump in here with the other school of thought just for the record. On a first flight with a new engine, I want maximum cooling during the flight, so I want the maximum air possible flowing through the cowl. I'm going to be running the engine hard anyway, pants on or off, so I don't see the point of having them off. But that's just me. Until you get your baffling checked out, oil cooler location verified, to me it just makes sense to have the maximum cooling possible especially during the break-in phase for the engine. Once the engine is broken in, then you can slow down. Having the pants on allows you to go faster and climb at a faster speed, if necessary.

The pants-off theory also has some valid points, I just think I prefer to err on the side of too much cooling. As always, in the end it's personal preference.
 
Cooling is in general a problem at low speeds. Even with spats off, an RV should be able to go plenty fast to get abundant cooling air.

I'll join up with the spats off folks for the first few flights, and enjoy being able to see the tires and brakes, have the extra drag if you need it, etc.

Ed
 
Off. You will want to be doing a thorough check of your brake connections, etc. after the early test flights. When you add the wheel pants you'll want to check for tire rubbing if you cut them very close. Especially after a firm landing.
 
I put mine on after 10 hrs and fixing the heavy wing problem (flap). After that I noticed the added cooling. It was summer.
 
Pat Hatch said:
OK, I'll jump in here with the other school of thought just for the record. On a first flight with a new engine, I want maximum cooling during the flight, so I want the maximum air possible flowing through the cowl. I'm going to be running the engine hard anyway, pants on or off, so I don't see the point of having them off. But that's just me. Until you get your baffling checked out, oil cooler location verified, to me it just makes sense to have the maximum cooling possible especially during the break-in phase for the engine. Once the engine is broken in, then you can slow down. Having the pants on allows you to go faster and climb at a faster speed, if necessary.

The pants-off theory also has some valid points, I just think I prefer to err on the side of too much cooling. As always, in the end it's personal preference.
Click to expand...

All valid points but since cooling is a factor of speed, you can just lower the nose slightly and climb at the same speed you would have with the pants and fairings installed. The ROC would only be impacted very slightly.

In level cruise, the speed difference should not be a factor for adequate break in cooling. If it is then there are other problems that should be resolved.

I always recommend no gear fairings for all of the reasons already mentioned.
 
I'm with Pat Hatch as usual. Put them on unless it's dead of winter. Especially if you've succumbed to the idea you can't go above 400 degrees CHT or 200 degrees oil temp!!!!!, like so many other ill informed others.;)
 
Charles in SC said:
What about the gear leg fairings? Should they be on? I understand they can have an affect on rigging as well.
Click to expand...

I'd tell you to put all of it on. If you need a little more performance (say an engine out glide), or a little better cooling, you'll be glad for the drag reduction. Later, once you've got your engine broken in and trustworthy, you can remove bits and pieces to verify trim/rig.
 
I like the idea of getting before/after airspeed numbers, so I think I'll leave mine off for at least the first couple of Phase 1 flights. Also, more cooling airflow on the ground for bedding in the brakes.
 
rightrudder said:
I like the idea of getting before/after airspeed numbers, so I think I'll leave mine off for at least the first couple of Phase 1 flights. Also, more cooling airflow on the ground for bedding in the brakes.
Click to expand...

In years and years of RV'ing, I have heard of a lot more problems getting good engine cooling than I have of people getting good cooling to bed in their brakes. Let's see - new brake pads versus re-ringing and honing glazed cylinders....I think that I'd bias my decision towards getting plenty of engine cooling air first.

Scott is correct that if properly built, to plans, RVs cool fine (although most are not at all over-cooled) - but not everyone has built numerous RV's, and not all get them right the first time.

Obviously, you can do initial flights either way - both methods work. But the greater unknown in my mind is engine cooling, and if I am breaking in an engine, I want all I can get.

An awful lot of how you see this problem depends on where you are based - in a cool climate or warm one - or at sea level or altitude. People's experience with engine cooling varies greatly if they live in cool climes or warm.
 
Last edited:
Spats

Just another data point was my RV-8 first flight. No spats, no fairings. IO-360 M1B with 10 to 1 compression. I was unable to get CHT's above about 290 or 295 and landed to add some blockers ahead of the cylinders. Ambient temp @ surface in mid 20's.
 
Have not flown with the pants off until today. I am waiting for new brake lines from TS to arrive. Thought it would be easier than removing them all over again. So, upon second landing of the day....the left main tube blew out. The plane wanted badly to depart the left side of the runway. I think I may need new brake pads now as well. Mostly the right ones.
Since I flew with the pants off, pulling the wheel was that much faster.
I vote OK for test flights and when you just want to see everything really well.
(if I had used the word spats... at the FBO... I think they would have made me leave) ;)
 
You must log in or register to reply here.