Prop and Tire Question

[Tom G]

The prop on my 46 BC12D has CM7445 stamped on the hub. Saturday I took off and flew with a friend of mine with his '46 BC12D. I appeared to out climb him but did I ever have a time keeping up with him. Do I have a climb prop? We went to look at his prop but couldn't find a number since there was a sticker over it. I was just about to the redline and indicating 105MPH and was still barely keeping up. I know his airspeed indicator reads low, could his tach read low as well?

One more question, I should know this but what is the correct air pressure for the tires. The other day they were at 10 pounds and I pumped them up to 20.

Thanks,
Tom Gilbertson
N95716

[Rick_Utley]

Re: Prop and Tire Question

The prop numbers I have are:
Climb 43
Std 45
Cruise 47

Tire pressure 20 Lbs. But some like them a bit softer...

Hope this helps.

[jgerard]

Re: Prop and Tire Question

I have had lots of props come back from the prop shop after re-twisting the pitch, and they never seem to change the numbers stamped on the side of the hub, only the ones on the face which are normally covered up by the spinner and plate. There are way more reasons than prop pitch that would cause 2 seemingly identical planes cruise at different speeds. Try swapping props with your buddy and see what happens.

Jason
N43643

[Dano"T"]

Re: Prop and Tire Question

I have a McCauley 1B90 71-44 on my BC12D-85 and people keep telling me that is too short for seaplane ops. The ATC on the BC12D-85 says prop not over 72" not under 70", but I was told to put a 74" prop on. I get 2350 indicated rpms on takeoff on wheels right now and I don't think the C-85 will wind up as fast with a 74" prop. Am I wrong? I do have a 74-43 prop....will this help seaplane ops?

[shawn coleman]

Re: Prop and Tire Question

as far as the tires i run around 6 to 8 lbs. im sure some one will say im wrong but have done it for 12 years with same set of tires with no problem and it takes some abuse off the gear try 8 lbs go fly and land then try 20 you will notice difference
shawn

[M Towsley]

Re: Prop and Tire Question

20 pounds is the correct pressure. When I ran, accidentally mind you, 6-8 pounds the plane would bounce and was squirrely on the ground. A lot of damage can be done to the rim and tires by not keeping the pressure up. The only time I air down a tire is when I am off-roading in the Jeep. Gives a bigger footprint and helps protect the trails. Dangerous though to drive at higher speeds. You'll get squirm and the tire will heat up. Works the same with aviation tires. Look up the following information from Goodyear Aviation Tires, it is quite lengthy but quite informative about aviation tire care: www.goodyearaviation.com/tirecare.html

Hope this helps!

[shawn coleman]

Re: Prop and Tire Question

Like I said earlier . I was sure somebody would disagree , and obviously a low tire on a car doing 60 will get hot and explode in time . but landing a Taylorcraft in the neighborhood of 30 miles an hour and slowing down to 5 Miles an hour is not going to generate enough heat to be even noticeable. And also , I suppose , if he were to drop your plane in on landing . you could possibly bang a rim but I would like to hope none of us would do that. Besides that , I do have to disagree on the landing characteristics at the lower tire pressure, first of all . everybody knows that a low tire does not role as freely as a tire . that is hard or up to full pressure, consequently at landing the tire does not want to role as freely as the fully pressurized one. So in the event of a possible loss of control or ground loop the airplane is not going to react as quick as it would with free rolling our fully inflated tires so consequently . it gives the pilot more time to react to a bad situation .

If I was landing on pavement , all the time . I would probably change my tire pressures . I just prefer to have them softer on dirt .

shawn

[jgerard]

Re: Prop and Tire Question

I keep about 12 psi in the 8.50's works fine on pavement, even less pressure when playing on the gravel bars. Been thinking about running the Gy 26" tires without tubes since they are designed to be tubeless they have a stiffer side-wall. Not sure if they will come off the bead in the rough stuff??? Not even sure how I can seat the bead with out a tube in the tire. If I ever get a set I'll let yawl know how it turns out.

Jason
N43643

[M Towsley]

Re: Prop and Tire Question

Take the time to read the Goodyear Aviation Tire info. For some reason I would think those folks might know what they are talking about. As for hard landings, apparently those don't occur for you, (or most other people flying Taylorcrafts?!?!?!?), I know they happen for me. (I enjoy practicing the skill it takes to land smoothly,with tires at the correct twenty p.s.i.). Hard landings aside, tires heat up just on the taxi out for takeoff and after landing. A tight turn a little too fast, a turn around a locked tire, can cause problems. I'll stick with the tire makers on this one. And I'm not talking turf, dirt or sandbars with those big 'ol balloon tires either, just plain old stock tires. You might get away with low tire pressure for the life of your tires but it only takes that one time, and I surely don't want to discover what happens.

[lktiller]

Re: Prop and Tire Question

mfgs write books to cover their rear end and for the worse case possibilities. Written for avg. heavier, faster craft.
T-craft at the low end of the operating specs.
90% of my taxi time is on grass. less than 10lbs in the tires. When I think to check it. --no problems on pavement.
Have landed on pavement with one tire flat. Took a bit more rpm to taxi out of the way! only problem was embarressment. Still running same tires eight or ten years old. No noticable wear.

[midniteflyer52]

Re: Prop and Tire Question

Greetings Tribe,
I've watched this thread on tire pressure with some interest. From my own experience let me add that if you are going to have the tires at a lower air pressure keep an eye on the valve stems. If it is on an angle and not coming straight though the rim the tire may be creeping on the rim taking the inner tube with it. This will happen with normal landings over a period of time. Eventually this action will put enough strain on the stem and tube to cause a failure at the worst possible time. It happened to me one day as I touched down for a wheel landing. Things got real exciting for about 30 seconds. In the end, I bought a new inner tube and repaired the broken wheel pant bracket on my Luscombe. We unmounted the other tire to inspect the inner tube and straighten the stem and then pumped both tires up to 20 lbs. I flew home feeling lucky and a lttle wiser.
Regards
Glen Brodeur
Tf #42
'41 BL

[shawn coleman]

Re: Prop and Tire Question

mfgs write books to cover their rear end and for the worse case possibilities. Written for avg. heavier, faster craft.
T-craft at the low end of the operating specs.
90% of my taxi time is on grass. less than 10lbs in the tires. When I think to check it. --no problems on pavement.
Have landed on pavement with one tire flat. Took a bit more rpm to taxi out of the way! only problem was embarressment. Still running same tires eight or ten years old. No noticable wear.

agree with you if a tcraft weighted 80,000 and landed 3 times faster i would agree with specs but its not the case like isaid i have ll years on my tires and they are wore but normal for age landed on rocks pavement grass an snow all with no problems but do agree on the valve stem issue never had a broblem but have seen it happen it seems you cant predict how a rim might bond to a tire and yes i know use more air , but taxi on a bad strip with hard tires and then tell me there is no differance in shock to your plane ??

what hurts worse getting hit in the head with a baseball or a ballon??

never realized this would be debated but love reading everyones opinion please dont take offence
shawn
f19 208ap

[Tom G]

Re: Prop and Tire Question

Thanks everyone for responding to this. We're going to switch props at some point and try it out. I'll let you know what happens.

[TimHicks]

Re: Prop and Tire Question

Tom,
I'm interested in what you find out from switching props. Be sure to post the results. One thing that I've noticed from flying formation with other TaylorCrafts is that it seems like whenever I'm flying lead at a normal cruise RPM (2150),straight and level, the other guy is hollering over the radio for me to slow down because he can't keep up. Then, when I'm flying trail, after desperately trying to keep up with him by pushing my engine to redline, I holler at him to slow down.
Tim

[N74DV]

Re: Prop and Tire Question

I found out today that 18lbs is my favorite. My tires were low so I put some air in them this afternoon. I have wheel pants and it's hard to check with a guage without taking the pants off so I just guessed.

well... that'll be the last time I guess. I flew it and on the first landing I quickly found out that she was very squirrley. Tried 3 m ore and they were the same. Brought her back in and pulled the wheel pants and measured and found I was at 30lb!

Dropped it down to 18lb and flew some more.... just right.