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CiES fuel Senders

bob865

Well Known Member
Hey all.

My wing kit is due in soon. I declined the Vans fuel senders when I ordered because I assumed I would install CiES senders. This is what I put in my Mooney when I did its refresh and they are great. Easily calibrated and very reliable. I hate the idea of putting resistive fuel senders in. Well now that I'm looking, this looks to be a problem. I'm not seeing CiES senders available for an RV-8. I did a quick search on VAF and came up dry. The best I saw was guys using a capacitive setup.

Has anyone done this?
 
Call

Call the company. I spoke with them at Oshkosh and they were ready to help. If I build again, I will use them…
 
I e-mailed CiES at the same time I posted and just got the following response. Thought I would share to document for the forum.

We have that aircraft covered.

If you are building it now, I have a question.

Our senders will not read the upper 5 gallons of fuel in the Van’s tanks; however, we have had several customers mount an extra sender in each tank to do read the top end.

Either way, simply fill out the order form and we can get started on your units. Current lead time is 4-6 weeks.

I have linked the order form below.

https://forms.gle/YbfH3jLYJyA6xRy67
 
Full readings

The only "single" sensor that will read the total fuel is if you build a capacitance system into your tanks; the stock floats, princeton capacitance probes, the CiES floats...none of them will read all of the fuel.

Doubling the CiES sensors will allow you to read it all. Realistically, though, with a properly calibrated fuel flow sensor, you don't need to be able to read all of the fuel. The single sensors will read "Full" until the fuel leveldrops to the top of the float/sensor and then will be accurate for the remaining quantity. The rest can be accounted for using the fuel flow/fuel used display (assuming you have one). For example, in my -10, the princeton probes only read from 0 to 17 gallons each side. The gauges show 17 gallons (full) until I burn 13 gallons from the monitored tank. This is verified using the FF/FU display on my G3x. From 17 gallons to 0, the gauges are quite accurate.

Would I like to see 0 - 30 gallons on each side? Yep, unfortunately that was a compromise in getting the QB wings...the tanks were already complete. No easy or practical way to change that now!

If I built again, I would definitely use the CiES sensors, and would likely consider doubling them to allow reading the entire fuel load...
 
+ plus 1 for Rocket Man

Completely logical , accurate and safe. Plus CEIS was very accommodating on my 4 to optimize float travel and avoid interference with the first baffle. They are now very responsive 😊
 
Missing the top few gallons is exactly how it works on my Mooney too and it's certified aircraft. Like you said, I don't really care about the top few. Now if it was the bottom few, I'd have a huge issue with it. Now I have to weigh my options to do a two sender install or go with 1 with the top few limitation.
 
Many certified aircraft use resistive senders in a summing (series) configuration to accurately gauge the tank when the tanks are full.
 
They are expensive!

True. But they are very precise and when properly calibrated very accurate too. When I installed them in my Mooney, it was the first time I flew a plane with fuel gauges I could trust. I'd rather spend 10x the money for something that works than 1/10 the price for something that doesn't. I mean if you think about it, $70 for senders you don't use is infinitely more expensive than $2000 for something you use every flight.
 
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Many certified aircraft use resistive senders in a summing (series) configuration to accurately gauge the tank when the tanks are full.

Yep. And CiES has a way to do the same. It's not resistive, but functions essentially the same way.
 
How'd it turn out?

Starting my tanks and researching senders. @bob865 did you end up going with 4 senders? How hard was it to install and calibrate? What did it end up costing in the end?

I didn't realize that senders are not included in the -10 wing kit so now weighing my options.

Saw the CEIS senders at OSH this summer and they do look like nice units.
 
I'm wondering if the price may come down as these become more widely used?

It looks like the lowest priced kit for a certificated airplane is $870 at ACS. Many companies offer a parallel product line for Experimental aircraft that they can offer for less money because they don't need to process and maintain all of the certification paperwork. If CiES would do the same, and hit a price point like, oh, howabout $350? I would go for them. I bet they would sell a ton of them.

I do use my old-school resistive units all the time, with the reinforcement of the fuel totalizing from the fuel flow sensor. So Bob865's argument doesn't apply. Do I totally trust them? No, but like I said, when they are in agreement with the fuel totalizer, that second vote tells me I can trust them 'enough' to know how much is in each tank.
 
Capacitive Sensors and different fuels

I had the capacitive sensors on my RV8 and loved them until I began using different fuels.

The calibration curves for 100LL do not match auto fuel. So, if you plan on using different fuels or a blend of fuel, take this into consideration.... (I am guessing the electrical properties of the fuel are different?)
 
Late reply to Everwild

My wings came in over a year late, so I haven't actually made the decision yet. I'm trying not to back out on my decision, but I am starting to second guess. Part of my reason for second guessing is I want to use Dynon for my panel and Dynon won't accept a frequency input (or at least last time I checked they wouldn't). The frequency input is less prone to variation from interference. If you have a minor electrical change (say a change in resistance for example), it won't affect the output if it's a frequency output. Whereas if I have to use a voltage input ALL electrical changes WILL affect the output., I'm not seeing how that is any better than resistive. They both have similar risks of interference. Plus one is a fraction of the cost, so that has some bearing on the decision.

On a side question for the group, how accessible are the senders once installed? How hard is it to change a sender if it needs to be changed?

Starting my tanks and researching senders. @bob865 did you end up going with 4 senders? How hard was it to install and calibrate? What did it end up costing in the end?

I didn't realize that senders are not included in the -10 wing kit so now weighing my options.

Saw the CEIS senders at OSH this summer and they do look like nice units.
 
On a side question for the group, how accessible are the senders once installed? How hard is it to change a sender if it needs to be changed?

Adam, on an RV-8, it is possible to change a tank sensor with the wings still installed. It is kind of tight, but it can be done. To make it easier, use hex-socket screws instead of phillips screws, so they can be turned with an allen wrench or short allen socket on a 1/4" drive ratchet handle.

Also, A lot harder to remove/replace if they are installed with ProSeal. I used the supplied rubber gaskets, coated with Permatex HiTAck gasket sealant, with great success, and easy to disassemble.
 
Also, A lot harder to remove/replace if they are installed with ProSeal. I used the supplied rubber gaskets, coated with Permatex HiTAck gasket sealant, with great success, and easy to disassemble.

I like that answer. I know the general consensus is to proseal them in, but I just hate everything about the idea of prosealing them in place.
 
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