Author Topic: What a difference good advice, and more castor makes! (Read 3834 times)

Brian Massey · « **on:** July 25, 2010, 11:08:50 PM »

I've been flying my Chipmonk with a B40 for only 25 flights or so, and this is over a period of close to 3 1/2 months due to my schedule. It seemed to fly (RE: engine runs) OK when I was in Eugene for the Northwest Regional in May (temps in the 70's). After my business trip, and when back home in Central CA the engine runs were erratic. Last Friday Richard Walbridge asked me what lub content I was running; 20% Byron fuel was my answer. He immediately suggested running more Castor. I re-blended an "old" can of Powermaster (10/22) to come up to 25.5 lub. WHAT A DIFFERENCE!!! Today I enjoyed 3 flights with near perfect engine runs . . . that's in Central CA in July with 100+ temps!

Many of you know who Richard Walbridge is; I've only recently become acquainted and can't be happier!! What an asset his knowledge is! Sorry Richard, hope you don't get tired of my questions!

Brian

Dick Pacini · « **Reply #1 on:** July 26, 2010, 09:41:52 PM »

I just read the instruction sheet for my NIB Brodak 40 and they specify 11.5% synthetic and 11.5% castor. Does the Byron 20 have any castor in it?

Brian Massey · « **Reply #2 on:** July 26, 2010, 10:06:18 PM »

Byron fuels don't state the castor/synthentic mix on their containers, but I think it's an 80%/20% syn to castor blend. My B40 operating in 100 degree temps really seems to prefer a much higher castor content.
When I was in Eugene for the Northwest Regionals, the temps were in the 70's and the straight Byrons seemed fine. When I got the plane back home in CA with 100+ degree temps the engine just didn't preform. With my new blend of 25.,5% percent lub, with that 64% being castor, the engine runs were great. I say that knowing I'll got out tomorrow morning "hoping" for a repeat preformance. I'll post tomorrow to let you know.

Brian

Dick Pacini · « **Reply #3 on:** July 26, 2010, 11:46:44 PM »

It may be 80% synthetic and 20% castor, but that percentage is of the total oil content. What is the % of oil in the fuel? If it is 20%, then 80% of that is synthetic and 20% is castor, or 16% synthetic and 4% castor = 20%. Brodak recommends 23% oil content of which 50% is synthetic and 50% castor (11.5% + 11.5% = 23%) Your castor was low from the get-go.

Mark Scarborough · « **Reply #4 on:** July 27, 2010, 12:17:33 AM »

Dick
My recollection is that Byron fuel is 18 % total oil.

Dick Pacini · « **Reply #5 on:** July 27, 2010, 06:37:58 AM »

Quote from: Mark Scarborough on July 27, 2010, 12:17:33 AM

Dick
My recollection is that Byron fuel is 18 % total oil.

If that is true, you were 5% low for as long as you used that fuel. Didn't you get a manual with your 40?

steven yampolsky · « **Reply #6 on:** July 27, 2010, 07:57:20 AM »

Quote from: Brian Massey on July 25, 2010, 11:08:50 PM

I've been flying my Chipmonk with a B40 for only 25 flights or so, and this is over a period of close to 3 1/2 months due to my schedule. It seemed to fly (RE: engine runs) OK when I was in Eugene for the Northwest Regional in May (temps in the 70's). After my business trip, and when back home in Central CA the engine runs were erratic. Last Friday Richard Walbridge asked me what lub content I was running; 20% Byron fuel was my answer. He immediately suggested running more Castor. I re-blended an "old" can of Powermaster (10/22) to come up to 25.5 lub. WHAT A DIFFERENCE!!! Today I enjoyed 3 flights with near perfect engine runs . . . that's in Central CA in July with 100+ temps!

Many of you know who Richard Walbridge is; I've only recently become acquainted and can't be happier!! What an asset his knowledge is! Sorry Richard, hope you don't get tired of my questions!

Brian

Brian, I have the same setup (Chipmunk w/B40). The motor requires a lot of flights to break in. In my case, the motor did not start to "settle" until flight 30 or so. That included 30 minutes of break in on the stand as per break in instructions. At this point, I have 100+ flights on my Chip and the engine is rock solid on 18% 50/50(syn/castor) mix.

I don't think you are doing the motor much good with all that extra castor. All it does is lower power output and lower exhaust temps. I suggest you stick with your previous blend and fly out the break in period. The way you can tell if the motor is broken in is looking at the consistency from flight to flight and fuel economy. If you get 10 consistent flights in the row and fuel economy is around 3 1/4 oz for 6:00 flight, then your engine is broken in.

Here are a few pics of my Chip:

Dick Pacini · « **Reply #7 on:** July 27, 2010, 09:10:29 AM »

Why not follow the manufacturer's recommendation for oil content? Brodak says 23% 50/50.

Brian Massey · « **Reply #8 on:** July 27, 2010, 09:19:10 AM »

Steven, Good looking Chip! I like your cowl treatment.

I've had thoughts that the engine wasn't really broken in yet. I followed the instructions for the breakin using Powermaster 10/22 fuel. Then when that became unavailable our hobby shop picked up the Byrons line. I bought the Byrons 10/20 and started flying with that. It seemed ok until the weather got hot (100+ temps) and then engine runs were not predictable. I was told that many in the Los Angeles area fly their B40's with a blend of 10/22 and 10/29 fuels mixed equally. That would give them about a 25.5% total oil (I believe both fuels were 50/50 blends). That's the number I brought my fuel up to; both the Byrons and the last 1/2 can of Powermaster I had on the shelf. I'll run these until gone then will switch to Powermaster 10/18 now that it's available again. I will add castor to bring the numbers up.

I'll watch the engine runs carefully and try to judge when it's truly broken in. I know consistancy will be a key. BTW, right now I'm using 4.5 oz for a slightly over 7 minute flight.

Brian Massey · « **Reply #9 on:** July 27, 2010, 09:23:01 AM »

Quote from: Dick Pacini on July 27, 2010, 09:10:29 AM

Why not follow the manufacturer's recommendation for oil content? Brodak says 23% 50/50.

I may go to that oil content after I burn what I have now. As Steven suggested, the engine may not be fully broken in. I'm getting ready to go fly now; I'm anxious to see how the engine runs are today.

Brian

Garf · « **Reply #10 on:** July 27, 2010, 01:11:02 PM »

I am also a believer in castor. My mix uses 15% castor and 5% klotz. Works pretty good in Miami.

steven yampolsky · « **Reply #11 on:** July 27, 2010, 02:33:51 PM »

Quote from: Brian Massey on July 27, 2010, 09:19:10 AM

I'll watch the engine runs carefully and try to judge when it's truly broken in. I know consistancy will be a key. BTW, right now I'm using 4.5 oz for a slightly over 7 minute flight.

I have to admit, most of my flying is at sea level and rarely above 100. That said, I have never had erratic runs due to high temps. 4.5oz for 7 min is a lot. Instead of adding oil, can you see if you can improve cooling instead?

Balsa Butcher · « **Reply #12 on:** July 27, 2010, 03:03:00 PM »

I have been running B-40's for awhile now. My "Brodak Brew" is Powermaster GMA 10/22 w/ 2.6 ounces of castor added to bring it up to (approximately)24% lube, 13% castor. It cures the tendency for B-40's (especially the not completely broken in ones) to speed up during the run. Not my idea, some So-Cal fliers enlightened me with that bit of info...it works.

4.5 ounces for a 7 minute run isn't excessive with the stock venturi. They are pretty strong engines and use more fuel than some others. I tried a smaller venturi but the run was not as consistent. Concluded that higer fuel consumption aided in cooling which resulted in better runs. Other's experience may differ.

Brian Massey · « **Reply #13 on:** July 28, 2010, 12:34:04 AM »

Quote from: Pete Cunha on July 27, 2010, 03:03:00 PM

I have been running B-40's for awhile now. My "Brodak Brew" is Powermaster GMA 10/22 w/ 2.6 ounces of castor added to bring it up to (approximately)24% lube, 13% castor. It cures the tendency for B-40's (especially the not completely broken in ones) to speed up during the run. Not my idea, some So-Cal fliers enlightened me with that bit of info...it works.

4.5 ounces for a 7 minute run isn't excessive with the stock venturi. They are pretty strong engines and use more fuel than some others. I tried a smaller venturi but the run was not as consistent. Concluded that higer fuel consumption aided in cooling which resulted in better runs. Other's experience may differ.

Thanks Pete; Richard Walbridge also told me that the B40 flyers in So Cal run higher oil (castor) content than the Brodak info sheet specifies. I got out today and got in 4 good runs. The temps were in the 90's with shifting 5-15mph winds. All runs were consistant; that's the good news. I had to bring the needle down slightly from the first flight (too lean/fast, but flyable) till the forth flight whch was near a perfect engine run. I think the engine is just really now breaking in, so I'll play the needle a bit now and then depending on the day. Based on today, a launch at 10,400 spinning a Master Airscrew 11/6 seems like a good starting point. Yea, I'm not unhappy with 4.5 oz per flight; I don't mind wiping excess castor off the under belly at all.

Brian

john e. holliday · « **Reply #14 on:** July 28, 2010, 09:08:11 AM »

Hope that is a wood MA. The composite props were okay on my twiddly stick planes but, could never get them to work in control line. Also I think 11-6 is a bit much, but what ever works for you. I use 11-4or 5 Top Flite Power Points in this neck of the woods. APC props work also. Also I have come to the conclusion that my B-40's will be broke in like my Fox's. Run on the bench long enough that they will hold a rich setting and then go fly. Making sure the engine is rich enough. Remember to let them to cool out between flights.

Balsa Butcher · « **Reply #15 on:** July 28, 2010, 09:36:12 AM »

Favorite B-40 Props: APC 10 1/2 X 4.5 (scimitar shape, launch around 10,600 rpm), ThunderTiger (cyclone) 11 x 4.5 (works good at sea level, argueabley too much prop above 2,500 msl) APC 11 x 4 (not my favorite but some have good luck with it). All inexpensive, readily available.

Brian Massey · « **Reply #16 on:** July 28, 2010, 10:25:55 AM »

John and Pete; thanks for the prop suggestions. I really haven't done any experimenting with them because I was focused on getting a few flights on the plane before the Northwest Regional. I think now might be the time, although I don't have a problem with what the 11/6 is doing. I don't have any of what you suggest, but it's time to place and order with Sam (or Tower) anyway.

Brian

steven yampolsky · « **Reply #17 on:** July 28, 2010, 03:46:13 PM »

Quote from: Pete Cunha on July 28, 2010, 09:36:12 AM

Favorite B-40 Props: APC 10 1/2 X 4.5 (scimitar shape, launch around 10,600 rpm), ThunderTiger (cyclone) 11 x 4.5 (works good at sea level, argueabley too much prop above 2,500 msl) APC 11 x 4 (not my favorite but some have good luck with it). All inexpensive, readily available.

I'd take Pete on his advice.

I find ThunderTiger 11x4.5 is the best on B40 with APC 10.5x4.5 a hair behind only because it's heavy(APC's are heavy!). 11x6 MA does not sounds like too much prop. B40 can swing those no problem but you are definitely loading up the motor(read "generating extra heat"). To be honest MA props are a step above paint stirrers. APC is a superb starter prop for your needs and you can pick it up at most hobby shops.

Randy Powell · « **Reply #18 on:** July 28, 2010, 04:08:39 PM »

Hmm, I have a Walter Umland Chip kit under the bench ...

Brian Massey · « **Reply #19 on:** July 28, 2010, 05:29:41 PM »

Quote from: Randy Powell on July 28, 2010, 04:08:39 PM

Hmm, I have a Walter Umland Chip kit under the bench ...

Go for it Randy!

Brian

steven yampolsky · « **Reply #20 on:** July 28, 2010, 07:52:37 PM »

Quote from: Randy Powell on July 28, 2010, 04:08:39 PM

Hmm, I have a Walter Umland Chip kit under the bench ...

Got B40?

Author Topic: What a difference good advice, and more castor makes! (Read 3834 times)

steven yampolsky

steven yampolsky

steven yampolsky

steven yampolsky