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Building fuel sender question

jcarne

Well Known Member
Patron
Good day everyone,
I am getting to the point where I need to plan my tanks and get things ordered as I will probably be working on them in less than a month. My question for you guys is on drawing OP07 there is a bill of materials for capacative fuel senders. The plates they list are T-813 but it does not show up on Van's "the list". So does anyone have the dimensions of this plate, mainly the width of it (the rest I can figure out by tracing a rib). Is there a better/ different way that people are doing fuel senders now? I tried to search the forums but no dice. Thanks!
 
Complete package

Do you already have the electronics for the cap fuel senders?
It sems these have fallen out of favor. May i suggest you check with Vans or other vendors?
 
No I have nothing as of yet for the senders. I have been looking at the Princeton fuel sensors but they are pricey at about $145 per tank. I would love to hear what most people these days are doing.
 
My tanks were built years ago by the initial builder with capacitance senders. I don't think Vans offers them any more in favor of the float type. They are finicky to get calibrated, in my experience.

The float type, you'll find work fine but they read full down to about 15 gallons due to their placement in the tank.

Also, float senders do not require a capacitance to voltage converter (~$50 each from Dynon).
 
My tanks were built years ago by the initial builder with capacitance senders. I don't think Vans offers them any more in favor of the float type. They are finicky to get calibrated, in my experience.

The float type, you'll find work fine but they read full down to about 15 gallons due to their placement in the tank.

Also, float senders do not require a capacitance to voltage converter (~$50 each from Dynon).

Interesting Raymo, I have heard of a few people having difficulties with capacative senders but I also heard of many people say how flippin accurate they are which is appealing for the relatively low cost. Every plane I have flown has only had float types on it and lets put it this way, I never once looked at the gauges because I was told not to trust them. Not to mention the fact that I don't think I have ever got into the airplane without visually checking the tanks.
 
My experience with them is that they are indeed finicky to calibrate correctly - but once that is done they are VERY accurate as long as you are constantly running the same type of fuel. I was running 91E10 mogas and 100LL as a mixture from 0% to 100% based on filling with mogas at home and 100LL on the road, and they have way different dielectric constants, so my readings were almost never accurate with a fuel mix in the tank other than 100% either way. I changed them out for float senders since they don't care what the mixture is, but if you stick to 100LL you'll be fine and you'll enjoy the accuracy - after you write the check for the higher cost of the components and of course the capacitance-to-voltage converters. Princeton converters are the best to have, IMHO.
 
I've got a full capacitive sender kit for my RV-7. I am using it as a template to buy the parts and sell a few kits.

I already have made several kits of the delrin spacers by cutting delrin stock on my laser cutter and they actually look better than the ones that Vans shipped (they were cut on a lathe and needed a bit of finishing work).

I am working with a few metal shops here in town to find someone who can punch a few lots of them using the Vans original plates as a template.

If I can get a full kit sourced, I am planning on asking Vans permission to start making a few and selling them. I'd probably have to come up with my own diagrams or installation pictures, as I doubt they give me permission to reproduce them.
 
I went with the floats, did the Dynon cal one gallon at a time, map it in the set up menu and your set. The sender readings are averaged out over a specific period of time to calculate for fuel in motion and appear to be very accurate under the 16 gallon start of the sweep.
 
airguy thanks for the reply, I read in a different thread where you were talking about the calibration problems, maybe something I need to consider as different fuels may be an option.

lynn I was wondering what you were up to with this as we are basically in the same spot. Let me know if you have any developments

Bret that is nice to know about the floats. I plan on using Dynon so it is nice to know that it is an accurate system should I go that route.
 
I've got a full capacitive sender kit for my RV-7. I am using it as a template to buy the parts and sell a few kits.

I already have made several kits of the delrin spacers by cutting delrin stock on my laser cutter and they actually look better than the ones that Vans shipped (they were cut on a lathe and needed a bit of finishing work).

I am working with a few metal shops here in town to find someone who can punch a few lots of them using the Vans original plates as a template.

If I can get a full kit sourced, I am planning on asking Vans permission to start making a few and selling them. I'd probably have to come up with my own diagrams or installation pictures, as I doubt they give me permission to reproduce them.

Lynn just as a side note I'm sure the plates could made by tracing a rib and subtracting the 5/32 from each edge as shown on OP07, the info that is not shown is how wide the plate is. The plate looks like it is 5" wide and I'm assuming it doesn't have to be exact as it will be calibrated anyways. If this is the case I may just make one.
 
I'll measure my plates tonight and let you know. The spacers are important to kept the mounting screws from grounding out on the rib. I've got some delrin spacers made up if you need a set. Pay shipping and I'll send you enough to do both tanks in return for feedback on them :)

You're a bit ahead of me on the build now. I haven't gotten to spend much time on my build lately. I have three certification exams to renew by the end of November in order to keep my RHCA certification up to date, and that has taken up much of my spare time.
 
I'll measure my plates tonight and let you know. The spacers are important to kept the mounting screws from grounding out on the rib. I've got some delrin spacers made up if you need a set. Pay shipping and I'll send you enough to do both tanks in return for feedback on them :)

You're a bit ahead of me on the build now. I haven't gotten to spend much time on my build lately. I have three certification exams to renew by the end of November in order to keep my RHCA certification up to date, and that has taken up much of my spare time.

Lynn thanks for the offer on the delrin. I have done some soul searching over the night and came to the realization that I am probably going to mix fuels as 100LL is not cheap were I live. Therefore I think it best I go with the floats as many have mentioned the inaccurate readings with capacative when fuel is mixed. Now I'm just wishing I hadn't deleted them off of my kit!:D Oh well, I have to order tank sealant anyways. Thanks for the replies guys!
 
I have two float fuel senders that I forgot to delete from the kit. I am going with capacitive and have no use for them.

I'll give you sweet deal: 1/2 price ($30 for the pair) donated to VAF.
 
I have two float fuel senders that I forgot to delete from the kit. I am going with capacitive and have no use for them.

I'll give you sweet deal: 1/2 price ($30 for the pair) donated to VAF.

That would be awesome! Just sent you a PM.
 
Capacitance Sender Plates

Mine are 5 3/8ths wide for an RV8.

CubedRoot, I sent you a PM...
 
I'll measure my plates tonight and let you know. The spacers are important to kept the mounting screws from grounding out on the rib. I've got some delrin spacers made up if you need a set. Pay shipping and I'll send you enough to do both tanks in return for feedback on them :)

And here I just ordered a few 3/4" delrin rods in order to do the same thing myself! I may take you up on that offer if mine don't turn out well (I don't have a lathe). Do yours use the same 1/4" holes thru the ribs that Vans recommends with their kit?
 
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