Hopefully this isn’t a stupid question. There is no mixture control on my Champ. It’s the first plane I have flown without one. I have about 100 hours in it so far and haven’t had it above 4,500’ msl. Most of the flying I do is below that, 2,000’ - 3,500’. However on the day where I want to get above mechanical turbulence (Like last Saturday) or catch a good tailwind Is there a point where it just doesn’t make sense or may be tough on the engine (fouled plugs, etc.)? Any info or advice would be appreciated.

Thanks,

Pete

Hello Pete, wife/I learned to fly in a 65HP Champ in 1981 here in Colo; mile hi and in summer we could easily get DAs of 10,000'. One winter we (both of us & full fuel) used power (what little bit we had) and ridge lift to get our 7AC/65HP to near the peak of Longs Peak which is a Colo 14er. I flew the Champ around the eastern side of the Rockies quite often up to 8K++ with DA of 11-12. Four years ago I bought a 7DC Champ (C85 with O-200 conversion) with 90-98HP, depends who you talk to. I flew this Champ at same altitudes using mostly power and what ridge lift I could get. Put 22" Desser tundra tires on and had a blast in AZ desert in dry creek bottoms following Huskies. Eventually, with Basic Med I decided I needed flaps and more HP and got my current Husky. Neighbor bought Champ and added new wings with more fuel and he will be flying DAs of 10-12 as well.

BTW, Stromberg carb does have a mixture but are so ineffective they are almost always hardwired open so no adjustment. Majority of small Contis have Stromberg carbs. We added a Marvel Schebler carb with mixture control when we majored C85/O-200 conversion three years ago.

Call me if you want to talk Champs.
Jack 303-356-7767

Like flyingJack said, your A65 likely has a Stromberg carburetor. Those have a sort of self adjusting mixture system that works reasonably well. The manual for them says you don’t need to mess with the mixture unless you are over 5000msl. I found that to be pretty much true.

Frequently the mixture was wired open but that wasn’t necessarily because it didn’t work well. It was mostly because airplane manufacturers wouldn’t have to install a mixture cable which saved money. Since most of there small airplanes were flown at lower elevations there wasn’t really a need for a mixture cable.

When we overhauled the C85 in the Luscombe we installed a mixture cable. The biggest issues is the mixture arm in the carburetor is really short so it took extremely fine adjusting to operate correctly. We extended the arm which made a huge difference. The engine ran much better at the elevations we fly are around here and we burned a lot less fuel. At your elevations I don’t think you’d need to bother with a mixture control.

I can back up what flyingjack said about 65 hp capability with ridge lift and thermal lift out of Gallup NM and all over the southern Rockys and Cumbres and La Vita passes to Denver. In 65, 75, and 85 hp engines with Stromberg carbs with mixture cable attached, I never had one that would change mixture in any way. All were somewhat high time engines. They all ran hot in the summer. The 90 hp Continental seemed to have improved, but still had the non-working adjustable Stromberg. It did not run as hot but turned slower than the 85 hp.

All those airplanes qualified as light sport well below 1340 max gross. They made great power gliders in the high desert and mountains. Thermal or orographic lift was pretty much required, given the limited fuel in Champ, Taylorcraft, Ercoupe, and early Cubs. I expect one could engine climb up pretty high in the early morning but might not have fuel to make the next watering hole. I was committed to all day operations anyway.

Whee reminded me of Luscombe. It was enough faster to maybe make it across the pass and to fuel with an engine climb into prevailing wind, but that extra speed beat the hell out of you later in the day. Dihedral of the low wing of the Ercoupe made for a pretty nice ride. Same with Cherokee, but that's another engine

If you have a Stromberg carb on a small Continental and want to learn how it actually works while debunking some of the myths that have plagued it:

http://www.bowersflybaby.com/tech/strom ... ecrets.pdf



If you don't have the Stromberg, you might still find some useful information in there that may interest you.

I flew an Airknocker up to a bit over 16k at one point in a couple of thermals from a 5000' field with a DA of 8000' at takeoff (so DA at 16k was really high). I finally got too chilly up that high, and the engine could run at almost full RPM. There was no sign of fouled plugs or anything like that on the way down.

It did have a mixture control that seemed to be effective. I was told it was a finnicky carb, and that would point to it probably being a Stromberg.

Thanks guys, One of the reasons I love this forum is the vast amount of practical knowledge and experience here. Jack, I might just take you up on that call. I do Indeed have a Stromberg Carb., which was rebuilt about 400 miles or so into the 1,400 mile ferry flight home. That’s a another story better told over some cold beers or a glass or two of good bourbon. I also learned the hard way about mo-gas and Delrin tips about a year ago and got some great advice from you all on that as well. Aryana, I read that entire article, excellent. Since the vast majority ( so far all) of my flights are below 5,000’ I will forget about mixture and turn my attention to the long list of other stuff I don’t know about old airplanes.

Pete

Reminds me of when I was in college. This old timer came to speak to our class, he was a heavy driver for some big airline. He talked about that stuff but what really stuck with me was him asking the class, "how much HP do you need to fly over the mountains?"

150!
180!
200!

were the replies from the class.

He says, "We used to fly between Glenwood and Denver all the time in 65HP cubs and champs"

Pick your days and learn how to use the lift issued to you by the world and you can do a lot.

Probably more story than you were after...

Though a huge fan of the Rotax 912S now, after 2700 hrs behind them, I sure wish it sounded like the A-65 in my previous T-Craft, especially the idle, nothing better!.

It did what it did rather quietly and gave no dangerous illusions of grandeur.