-
Welcome to the new Commander Owners Group Forums. Please bear with us as the kinks are worked out and things are tweaked. If you have any questions or issues with the new platform, please post them here.
The "8 Knot Mod"
- Thread starter jrichards
- Start date
I paid $85 per hour as well.
C
can114
Guest
Re: The "8 Knot Mod"
Jim,
Any news on the tail modification STC?
Jim,
Any news on the tail modification STC?
South Burlington, VT
- Aircraft Year
- 1978 580
- Aircraft Type
- Super Commander
- Reg Number
- N555LP
- Serial Number
- 14405
Re: The "8 Knot Mod"
Hi Wynand,
It's been a very busy summer and fall for me with engineering projects to restore several Commanders to safe and fast condition, completing certification of the 390, and building Super 580 No. 12 for Richard. Now planning to continue with test flights of the tail mod in Jan.
Best holiday wishes,
Jim
Hi Wynand,
It's been a very busy summer and fall for me with engineering projects to restore several Commanders to safe and fast condition, completing certification of the 390, and building Super 580 No. 12 for Richard. Now planning to continue with test flights of the tail mod in Jan.
Best holiday wishes,
Jim
Alex
New member
Edmond, OK
- Aircraft Year
- 1977
- Aircraft Type
- 114
- Reg Number
- N900CD
- Serial Number
- 14213
Chelsea, MI
- Aircraft Year
- 1995
- Aircraft Type
- Super Commander
- Reg Number
- N114KJ
- Serial Number
- 14630
Re: The "8 Knot Mod"
The whole way 15-20 kts headwind component. I had to fly low to keep it down to that. It was interesting on departure, took off in 700/3 18G30, and winds were 75kts out of the southeast by 3000 ft. They diminished rapidly as we proceeded southwest. We were planning on going back tomorrow, but the headwinds are even worse going back, so I'm trying to convince the family to wait a day. I guess we aren't die hards like some of you, 7 hours in a row of seat time was too much for 4 of us.
The whole way 15-20 kts headwind component. I had to fly low to keep it down to that. It was interesting on departure, took off in 700/3 18G30, and winds were 75kts out of the southeast by 3000 ft. They diminished rapidly as we proceeded southwest. We were planning on going back tomorrow, but the headwinds are even worse going back, so I'm trying to convince the family to wait a day. I guess we aren't die hards like some of you, 7 hours in a row of seat time was too much for 4 of us.
Davis, CA
- Aircraft Year
- 1975
- Aircraft Type
- 112 Hot Shot
- Reg Number
- N1286J
- Serial Number
- 286
Re: The "8 Knot Mod"
Jim,
Just curious -- how is the tail mod (so-called 8 knot mod) coming?
Regards,
Neal
Jim,
Just curious -- how is the tail mod (so-called 8 knot mod) coming?
Regards,
Neal
South Burlington, VT
- Aircraft Year
- 1978 580
- Aircraft Type
- Super Commander
- Reg Number
- N555LP
- Serial Number
- 14405
Re: The "8 Knot Mod"
Hi Neal,
I have modified my 31J and flown once thus far. The streamlining is better but I am making some adjustments before flying for solid comparative numbers.
Jim
Hi Neal,
I have modified my 31J and flown once thus far. The streamlining is better but I am making some adjustments before flying for solid comparative numbers.
Jim
South Burlington, VT
- Aircraft Year
- 1978 580
- Aircraft Type
- Super Commander
- Reg Number
- N555LP
- Serial Number
- 14405
Re: The "8 Knot Mod"
Hi All,
For those waiting on more news of the 8-knot mod, here's something to wet your appetites:
My '76 114, with her stab reset 1/2" higher at the leading edge is now flying the fastest I have ever experienced in any standard engine 114. She is truing at 160 KTAS and flying with almost perfectly streamlined elevator and trim tabs, actually just about 0.3" down elevator and .2" up tab at the top of the green arc. The only other AC11's I have ever seen fly this well "streamed" were 112's flying much slower.
31J has none of the usual speed mods: no NACA dorsal, no gap seals, no root fairings, no chops, 7.00 tires, the higher-drag Rockwell cowling and relatively tired paint. While I can't afford to put all these tricks on her at the moment, I would guess a solid +5 KTAS all tolled, so things are indeed starting to get very interesting.
From our test flights to date, we are inclined to believe Robin was right on the money in selecting 5/8" as the ideal incidence change. I had guessed that the higher average KIAS on the 114's would mean I would want a little less incidence change because of increased control authority at higher indicated airspeeds, hence my start at 1/2".
Oh well, it's just another round of tail disasm/reasm, and we are getting quite good at that. Next week, we'll take some same-day comparative numbers at 0 and 1/2", and then change to 5/8" and take the comparatives again.
Jim
Hi All,
For those waiting on more news of the 8-knot mod, here's something to wet your appetites:
My '76 114, with her stab reset 1/2" higher at the leading edge is now flying the fastest I have ever experienced in any standard engine 114. She is truing at 160 KTAS and flying with almost perfectly streamlined elevator and trim tabs, actually just about 0.3" down elevator and .2" up tab at the top of the green arc. The only other AC11's I have ever seen fly this well "streamed" were 112's flying much slower.
31J has none of the usual speed mods: no NACA dorsal, no gap seals, no root fairings, no chops, 7.00 tires, the higher-drag Rockwell cowling and relatively tired paint. While I can't afford to put all these tricks on her at the moment, I would guess a solid +5 KTAS all tolled, so things are indeed starting to get very interesting.
From our test flights to date, we are inclined to believe Robin was right on the money in selecting 5/8" as the ideal incidence change. I had guessed that the higher average KIAS on the 114's would mean I would want a little less incidence change because of increased control authority at higher indicated airspeeds, hence my start at 1/2".
Oh well, it's just another round of tail disasm/reasm, and we are getting quite good at that. Next week, we'll take some same-day comparative numbers at 0 and 1/2", and then change to 5/8" and take the comparatives again.
Jim
Last edited:
alandotson
New member
Full time RVer... 2010 Tiffin Phaeton 40QTH
- Aircraft Year
- 1977
- Aircraft Type
- 112TCA
- Reg Number
- N76CR
- Serial Number
- 13181
Re: The "8 Knot Mod"
Jim, will all models be the same mod? Or will each require flight testing and minor variances in the incidence? I have a TCA which might still be an unknown and different from the Robin's 112 or your 114.
Alan
Jim, will all models be the same mod? Or will each require flight testing and minor variances in the incidence? I have a TCA which might still be an unknown and different from the Robin's 112 or your 114.
Alan
One AMU per?
South Burlington, VT
- Aircraft Year
- 1978 580
- Aircraft Type
- Super Commander
- Reg Number
- N555LP
- Serial Number
- 14405
Re: The "8 Knot Mod"
Hi All,
My post may have been confusing.
The 5 knot reference was my guess at the added benefit of all the speed mods that are NOT on 31J: naca, gaps, chops, seals, etc. I have not reported the speed gains from the stab mod yet, only that 31J is doing 160 with the mod tail but NONE of the other mods.
Not sure yet if a single incidence setting will reasonably well suit all models, but I am seeking approval for any increase up to a certain maximum, and it won't be hard for us to supply the parts for different settings if worthwhile.
Jim
Hi All,
My post may have been confusing.
The 5 knot reference was my guess at the added benefit of all the speed mods that are NOT on 31J: naca, gaps, chops, seals, etc. I have not reported the speed gains from the stab mod yet, only that 31J is doing 160 with the mod tail but NONE of the other mods.
Not sure yet if a single incidence setting will reasonably well suit all models, but I am seeking approval for any increase up to a certain maximum, and it won't be hard for us to supply the parts for different settings if worthwhile.
Jim
Last edited: