I have a goofy question... I just bought this 172D with the Franklin 220 conversion. My question is: Why isn't there a flap restriction with this conversion? Most of the 180HP conversions have a flap restriction of 30 degrees. In this bird, I can go all the way to 40 Degrees (and I like it!). Why do they have a restriction in other conversions?

Just curious if any of you have an idea?

Thanks!

Jim

Flap restriction is only if you opt for the gross weight increase. Some conversions allow up for 2500 gross i think. Worried about ham handed pilots not raising 40 deg of flaps in a full gross go around.

Mark Y. wrote:Flap restriction is only if you opt for the gross weight increase. Some conversions allow up for 2500 gross i think. Worried about ham handed pilots not raising 40 deg of flaps in a full gross go around.

I've always been curious about te 172 restriction. So is it ham-fisted pilots not raising full flaps and not having enough horizontal stab and elevator?

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Mark Y. wrote:Flap restriction is only if you opt for the gross weight increase. Some conversions allow up for 2500 gross i think. Worried about ham handed pilots not raising 40 deg of flaps in a full gross go around.

AHHHHH! Thanks! This one has a 2,300LB GW. Makes sense! Even with 2,300, I still have a 900LB useful load, so I'm good!

Jim

No opinion on the flaps, but I just realized I was sitting at the table today when you were talking about your 172 (the guy in the red Cessna shirt). Meant to ask if you were on BCP as you were mentioning your plans for your bird, but got distracted. Nice to see another BCP face out there!

Not sure what the issue is exactly. masked elevator or too much drag. My bet would be on the added drag. I never tried when i had my N model with 40 deg of flaps. I know my flight training always beat it in to me, full throttle and flaps to 20 deg in a go around. Didn't matter if there was 30 or 40 deg out. I would never give up the 40 deg.

Did the N model even have 40? I love the 40 in my 65 model. Thing flies slow!

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colopilot wrote:No opinion on the flaps, but I just realized I was sitting at the table today when you were talking about your 172 (the guy in the red Cessna shirt). Meant to ask if you were on BCP as you were mentioning your plans for your bird, but got distracted. Nice to see another BCP face out there!

Right on dude! Next time you're out my hangars are in T-83 - Swing by, I always have cold drinks! I'm headed to Glenwood in the morning to start the real upgrades. I'll be gone for a week, but I'm out there most days!

Jim

jaudette wrote:

colopilot wrote:No opinion on the flaps, but I just realized I was sitting at the table today when you were talking about your 172 (the guy in the red Cessna shirt). Meant to ask if you were on BCP as you were mentioning your plans for your bird, but got distracted. Nice to see another BCP face out there!

Right on dude! Next time you're out my hangars are in T-83 - Swing by, I always have cold drinks! I'm headed to Glenwood in the morning to start the real upgrades. I'll be gone for a week, but I'm out there most days!

Jim

Cool! I'm in T-41. Out there some days, just depends on whatever else is going on. I take a lot of conference calls from the tarmac. I'm still planning my upgrades (Dynon really made some enticing promises last week), but at the moment hoping to get some alternator conversion gremlins sorted out ASAP so I can fly it again.

- Ralph

Ya, the 1977 12 volt N still had 40 deg.

Jaudette [sp]

Does your firewall have a "step" on the upper few inches?

If not - then usually no gross weight change was allowed- SO-
flap use stays the same.

Harry Delicker was always mad because he could not get
the gross weight increase for 170s or 172s with a FLAT firewall.

He did get IT for the 172 with a step in the firewall- flew his.

Believe there is some obscure design requirement that the plane
must be able to do a gross weight take off -[go around]- with full flaps
as with a flap mechanism failure.

The CG can be a problem for 170s with the extra
HP and CS Prop weight up front.

Nuff for now

Chris C

I sure like having 40 flaps--I use all 40 for 90% of my landings.

With my conversion, the 2500# gross weight of a normal P172D was reduced to 2350#. I don't know that I've ever done a go around at near full gross and 40 flaps, but I've done several while pretty heavy with all 40 hanging out. There's nothing unusual about it--just power up, get the flaps up midway while it accelerates and starts to climb, then all the way up when there's enough airspeed. Having manual flaps makes that pretty easy.

I think the closest I came to doing that at full gross was several years ago at OSH. I was on short final to 36L and an RV-something refused to taxi into the grass. I'd only burned off the fuel from DBQ to OSH, so I suppose I'd burned off maybe 11 gallons. Tower told me to go around at about 100', and other than having to delay getting in, it wasn't any big deal.

Cary

Cary wrote:........With my conversion, the 2500# gross weight of a normal P172D was reduced to 2350#.....

A horsepower upgrade conversion reduced the gross weight? Interesting....

Mark Y. wrote:Not sure what the issue is exactly. masked elevator or too much drag. My bet would be on the added drag. I never tried when i had my N model with 40 deg of flaps. I know my flight training always beat it in to me, full throttle and flaps to 20 deg in a go around. Didn't matter if there was 30 or 40 deg out. I would never give up the 40 deg.

Your flight instructor beat that into you because of the lessons learned by people before you.

If you've got 40 degrees hanging out and are trimmed hands off, and firewall the engine you will have your hands full - no kidding.

If you're prepared you can firewall it and set flaps 20 immediately (exactly as you were taught) and pin the cowl on the horizon until you see positive rate of climb, etc.

You'll be pushing very hard on the yoke until you've got that 20 degrees selected at which point you can reach the trim wheel and get some relief.

Just wait until you're mushing along in a simulated go around and your student slaps the flap lever into the UP position. She commented later that she had never seen my hand move that fast.

I fully agree, the elevator pressure to hold the nose down is crazy in a last sec go around while trimmed for landing with full flaps. Low speed, low lift, low to the ground with abnormally high control pressures is a recipe for disaster unless you are on your A-game. Add in a setting sun in your face to obscure your horizon view and maybe an over gross airplane and it could be too much going on for a low-time pilot to handle.

While agree that the elevator pressure in a go around is a lot, it's not as bad as say a 180 or 182 trimmed full nose up. These planes have not been limited to 30* of flap. So is it more an issue that the 172 is a trainer? Or is there some other factor that plays into the limitation?

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A1Skinner wrote:While agree that the elevator pressure in a go around is a lot, it's not as bad as say a 180 or 182 trimmed full nose up. These planes have not been limited to 30* of flap. So is it more an issue that the 172 is a trainer? Or is there some other factor that plays into the limitation?

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Like I said above, I like having 40 flaps in my P172D and use them routinely. But honestly, there's not a lot of difference between 30 and 40--a bit more drag with 40, but not so much that it will make a huge difference in the ability to get into a tight strip. And similarly, there's very little difference between the yoke pressure on a go-around if trimmed for approach with 30 hanging out or with 40 hanging out. Either is totally controllable. So my answer to your questions is, I don't know!

Cary

Underwood Aerial Patrol had a N Model 172 with electric flaps that went all the way down once you pushed down on the lever. I had never flown that airplane. I was to make the weather check on a very low ceiling day. Rolling on takeoff I decided to use some flap all the way around the pattern. The visibility turned out to be unworkable and I made one circuit and returned. I had been busy all the way around. Pulling up to report to the other pilot, he asked, "did you know the flaps were full down all the way around? "