Alcor STP vs. Decalin RunUp

[drseti]

I'm running a 912ULS in an Evektor SportStar S-LSA, using 100LL. Rotax previously recommended adding Alcor TCP, 1 oz per 10 gals of fuel, to scavenge lead. I've read that they are no longer recommending this, due to the corrosive nature of TCP. Some have suggested Decalin RunUp instead. However, the Decalin specs say:
"Decalin RunUp is not approved for use in the engines of certified aircraft."
Decalin is being marketed to the homebuilt community, and apparently is widely used in Rotax engines that have to run on 100LL. So, my question is, does an S-LSA constitute a certified aircraft? Is it legal (or safe) to use Decalin in a Rotax 912 installed in an S-LSA?

[roger lee]

Hi Drseti,

SLSA are not certified aircraft. Yes it's legal. You can use Decalin and many are with just as good a results as TCP. I have never liked TCP because of the harsh chemicals. I have been using Decalin in my 912's for over 1300 hrs. Aircraft Spruce has it for about $19. I states on the label to use 1/2 oz. per 10 gals. Works for me.
Now if you have a choice don't run 100LL at all. I use 91 Oct. all the time unless I'm traveling and I get stuck with 100LL.

[drseti]

Thanks for the prompt and concise response, Roger.

Now if you have a choice don't run 100LL at all. I use 91 Oct. all the time unless I'm traveling and I get stuck with 100LL.

Unfortunately, I can't find 91 octane mogas in this part of the country that doesn't have 10% ethanol. So, I'm stuck with 100LL.

Safe skies,
Paul

[roger lee]

Hi Paul,

Can't you use 91 Oct? What engine do you have? The Rotax's can all use 91 oct. Even the Jabiru came out with an SB saying you could use 91 Oct. Your fuel hoses should be ok and most, but not all peoples fuel tanks are ok. Rotax authorizes 10% ethanol.

[drseti]

Rotax authorizes 10% ethanol.

That's true, Roger, and I'm running the Rotax 912ULS, so the engine's OK. But, the airframe is an Evektor SportStar, and Evektor has not authorized ethanol.

I know that Remos, for example, is doing testing, to be able to authorize ethanol in their aircraft. They have a complete fuel delivery system (tanks, hoses, seals, pump, the works!) soaking in an ethanol tank even as we speak. After a month of this, they plan to do extensive testing of all fuel components, and if nothing is amiss, they will issue a service bulletin authorizing 91 octane E10.

I wish Evektor would follow their lead, and do similar testing, but so far they have not. So, until the airframe manufacturer authorizes it, I'm hesitant to use mogas.

Safe skies,
Paul

[FLA-CFI]

Hi Drseti,

SLSA are not certified aircraft. Yes it's legal. You can use Decalin and many are with just as good a results as TCP. I have never liked TCP because of the harsh chemicals. I have been using Decalin in my 912's for over 1300 hrs. Aircraft Spruce has it for about $19. I states on the label to use 1/2 oz. per 10 gals. Works for me.
Now if you have a choice don't run 100LL at all. I use 91 Oct. all the time unless I'm traveling and I get stuck with 100LL.

As an SLSA you have to follow what the manufacturer says. If Rotax (the engine manufacturer) and the aircraft manufacturer says you can use it then you are fine to use it. If they don't say anything on it you'll have to get them to issue a LOA Letter of authorization. You can't just go dumping anything you want in your tank...unless it is an ELSA then do as you please. But as a "Speical" Light Sport Aircraft you have to follow exactly what the manufacture says.

[Helen]

A while back when Alcor stopped shipping TCP, Spruce sent me a box of Decalin. The stuff had brown flakes in it and I sent it back. I suspect that the stuff was just old but I wouldn't feel comfortable running stuff now that I know it can deteriorate into gunk running through my carburetors. Alcor's TCP is certified also I know there's a reasonable amount of quality control in its manufacture and stability.

BTW, following the thread on this list about airframe cert for using MoGas for a Rotax, we had the AOPA sweepstakes Remos in the hangar for some work a few weeks ago and I had a chance to talk to them about it. AOPA apparently looked into doing just that and was told that when someone had tried that, the ethanol had dissolved the Remos's fuel tank turning it into "black goo." Do be certain to check with your airframe manufacturer before running anything with ethanol,especially if you don't have metal tanks.

Helen