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RV-14 QB Fuel Tank Float Clearance

Meat

Active Member
Hi All,

I'm installing the fuel level senders in my QB tanks. I've bent both float wires to match the template on p. 18-10, Rev 1. Both match all measurements exactly. With the senders and floats temporarily installed in the tanks I did continuity checks and got the same results as on my bench. Both read 246 ohms at full down to 30 ohms full up. However, both floats are hitting the top skins at the full up position. On p. 18-07, Rev 1 it specifies a minimum 1/16" clearance from the top and bottom skins. I could bend the wire more at the 90 deg point to increase clearance from the top skin but geometrically this will just bring the float into contact with the bottom skins. Not being able to see into the tanks certainly complicates things. Before I start chasing this down and/or fabricating new wires with guess-work measurements (since the plans measurements didn't work and I can't see in the tanks) I thought I'd ask you all.

My questions are:

1. Anyone know the reason for the 1/16" skin clearance?

2. What bad things will happen if the float actually touches the skin? The only negative I can see is rubbing with the float wire and wing skins issue over time. Maybe a small dab of Proseal on the float wire where it touches to alleviate that?

3. Anyone with the same issue and how did you handle it?

4. Anyone out there flying with your floats touching either skin? Did you have any negative issues?

I'll be asking Van's Tech Support as well but thought I'd put it to you folks too. I appreciate everyone's time and advice.

Cheers,
Scott
 
I ended up modifying the shape of the arm to get full clearance inside tank etc.

I think Vans may have modified the KAI more recently to account for issues with float arm.

IMG_4242.jpg
 
Here is how I did mine. They work well and I get full excursion.
 

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Thanks guys. Great solutions. I can stick my borescope in there to confirm clearances.

Scott
 
Just did mine with these new directions and the drawing on the last page of the section. I ended up with 0.25" clearance top and bottom. Seemed perfect.
 
I just did mine as well with the new dimensions. I found I had to overbend by a few degrees to avoid hitting the top skin. But only by a couple degrees.
 
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