First inspection on an RV

[kcabpilot]

Hi folks, I'm new here on the forum and I'm not an RV owner or builder but an A&P/IA doing a conditional inspection for an owner who is not the builder of an RV4. I've found lots of good info and a really great inspection checklist online but I still have a couple of questions about some stuff that came up during my inspection and figured now would be a good time to join the VAF forums.

So here are my questions:

1. Right hand wing flap hinge pin extends past the inboard aileron hinge and the aileron hinge hits it before getting to the stops. I noticed that the left wing flap hinge pin is trimmed shorter and doesn't interfere but I don't see anything to secure the hinge pin so I'm not sure if it's better for it to extend all the way or to be trimmed because if it migrates it might catch onto the aileron hinge which might be worse.

2. On the left wing the inboard aileron hinge bolt comes awfully close to the upper flap skin when the flaps are down - maybe 1/32 inch clearance. It's probably not an issue because I don't think the flaps would ever be down that far in flight due to the aerodynamic load but I'm not used to seeing clearances so tight and I've read that it's a common problem (being too close)

3. The fuel system is an Airflow Performance FM-200 and there is no gascolator. Is this normal? The only fuel drains appear to be the tank sumps.

Anyway, I'm looking forward to learning more about the RV's they are definitely great airplanes and so all tips and advice are welcome.

 

[kiwipete]

On the maint. issues:

1) The hinge pin needs something to stop it migrating. There was a disscussion in the past few days on this:

http://www.vansairforce.com/community/showthread.php?t=20409&highlight=flap+hinge


2) That clearence sounds a bit tight but without seeing a picture not sure what to suggest.

3) For a fuel injected system this is the normal Van's setup.

Hope this helps

Peter

 

[flion]

For #2, it's because the hinge bracket is flush with the end of the aileron. So the bolt head is actually in the gap between the flap and aileron. There should be little chance of the flap and aileron getting closer together, allowing the bolt head to impact the skin, but you could relieve the skin there for more clearance. Personally, I would not unless an inspection revealed evidence of contact. My big issue with this was that this bolt had to be installed this way because there was not enough room for the nut to be on that side of the hinge. However, if the nut ever came off, the bolt could migrate toward the flap, potentially jamming both surfaces. With no other choice, this area becomes a preflight inspection item.

 

[az_gila]

Pat describes the geometry...

.....
2. On the left wing the inboard aileron hinge bolt comes awfully close to the upper flap skin when the flaps are down - maybe 1/32 inch clearance. It's probably not an issue because I don't think the flaps would ever be down that far in flight due to the aerodynamic load but I'm not used to seeing clearances so tight and I've read that it's a common problem (being too close)

.....

...well in the above post.

However, there is also some variation placing the aileron on the wing in a spanwise direction with the use of spacers/washers on the two hinge bolts.

Perhaps the aileron has been removed in the past, and re-installed with the spacers in a different postion? Check the inboard and outboard gaps for equal size.

 

[kcabpilot]

Thanks for the replies

On #1 - I can see it's a common issue and even though the aileron hinge bracket contacts the flap hinge pin it does not prevent the aileron from reaching the stops as you can just force it and the hinge pin end gives enough to let it reach full travel. So I'm just pointing it out to the owner, the left side is trimmed shorter and clears but it's possible the pin could migrate outboard and start 'sawing' on the hinge bracket but there is no evidence of it ever having done that so I think it's basically a preflight check item.

On #2 - the clearance issue is only with flaps full down and aileron at full travel. Although it's close I see no evidence of actual contact and I don't think that this position is achievable in flight because of the aerodynamic loads on the flaps so I believe it's a non-issue, especially since the aileron hinges are normal preflight check items.

On #3 - found someone that is going to let me copy his Airflow Precision manual so I can bone up on the system and get more familiar with what I am looking at.

One other thing - the new owner is redoing the panel, removing all of the old IFR instrumentation and panel mounting a Garmin 396. He wants me to replace the batwing nav/com antenna with a standard com but when shopping online I noticed some pretty slick combo antennas that have com/gps/and xm all in one. I was thinking that given the tight quarters of an RV4 it might be nice to have all of that stuff out of the way. They ain't exactly cheap though.

Anyone out there have one or have any suggestions as to brand?