210 gear door mod?

[GA Driver]

Just a quick question. I watched an older 'strutted' 210 get airborne infront of me the other day and as the gear was raised I noticed it still had the old gear doors instead of the 'holes.' Haven't seen this on a 210 in awhile.
Anyone know the reason for their removal and replacement with the cutouts?

Was it done to the 337 also?

Cheers
GA Driver

[Richo]

Hello GA Driver

The C201 range started coming out without main gear doors from about 1994 with the J and P models. I don't know for sure, but belive this is because the "Holes" are behind the laminar flow breakaway point so there was no benifit in having doors back there. As mentiond in the gear door in the turn thread, removing the doors actualy has some benifit with weight and the turn problem.

The door mod for older C210 models came out in late 80's and resulted in the removal of the doors and the bulges where they fitted against the fuselage. The replacement skin came pre cut with the elongated holes for the wheels. The mod also removed some weight in the form of the door actuators and associated plumbing.

I am not aware that the very early C210 A through C models with the struts can have a door mods done. This is due to the type of undercaraige and retraction system used on these older machines. The early ones have spring leaf type legs which seem to defy all sorts of laws of physics when they retract. The later C210 have drop and retract upwards, tube legs which I imagine is due to better engineering and material strength which became avaialable as the type progressed.

I think there may still be a few of the later models still flying with doors on them, but they are rare as the mod reduces not only weight and drag but cost at maintenance as well.

Richo

[PILAME]

I think you will find that the 210 N was the first model without the gear doors. Cessna started making 210N's in about 1978. All 210's prior to this came out with gear doors but most have been modified. The 210 R was the last model 210 made. it didn't have gear doors either. Very nice aircraft, there are only a handful in Australia.

There is also a mod kit for the 337. If you get up to Broome you will see one up there. It doesn't look very nice on the 337 as the cutout is alot bigger. Here is a photo of a 337 with the mod.

http://airliners.net/open.file/209313/L/

:D :D :D

[the wizard of auz]

The gear mod on the 337 might not look good but I bet it saves a few sweaty moments on a hot day when heavy. the gear retraction was worth about ten knots usually, and stopped the climb altogether on a hot day. I managed a few sheepish grins when the pax asked if all was alright and if we were going to land again.
all the 210s that I have flown with the mod done are actually faster than when the doors were on.

[flying_phonebox]

Flown with doors and without and thought that having the doors gave ~5 kts but maybe it just seemed quicker cos of the lower Vle!

Pumping out the doors during a pre-flight get a few wandering glances....

[magnum pi]

Gear doors were removed on C210N models onwards to save costs & as a result the factory tests showed no change in cabin noise levels & a slight increase in IAS. Try to find a book called "WINGS FOR THE WORLD", it has the full story of every Cessna single made(up to & incl the caravan ). I think the authors name was Bill Thompson ?.

[185skywagon]

our 210M still has the gear doors. 165 kts TAS. system works well, provided your understand it and keep all the moving parts clean and lubed. getting rid of the doors removes about 150 moving parts, i think. just replaced a gear door last year at $3000.
if you raise the gear below 85 kts, you are in a dangerous zone re drag.
regards,

[bush mechanics]

Richo,
Sounds like you are still full of @#$%
1994 model Id like to see that,All Ns came out without maingear doors whent from hyd nose gear doors to mechanicaly actuated doors.They also dont have Uplocks,the gear is held in the up pos by hyd press.Stops the problem with uplocks not unlocking and the gear failing to come down,which did happen a bit with M models with full gear door set up.
Skywagon you are corect,If you keep everything clean and lubed normally no probs.But mix in red dirt and crappy strips they dont last long.Ive caried out this mod on one of our Ms and you do save a fair bit in weight.plus the clam doors on the main gear on our a/c were bent bacwards from someone lowering the gear at N model speeds.

[Transition Layer]

Have just flown my first 210 with gear doors in the past few weeks, and would have to say it is definitely slower than those that have had the mod done. Probably in the order of 5kts IAS. Could be just the machine though...

The extension/retraction cycles are obviously longer, which is more annoying than anything, waiting for that little green light. If anything, having the gear doors makes the aeroplane look a little smarter when it's on the ground (and probably in the air too).

I hadn't flown a 210 for quite a while up until a fortnight ago - brought back some sweet sweet memories :D

TL

[185skywagon]

bush mech,
we operate our 210m at Charleville. regularly in and out of red dirt and black soil strips. if anything, the gear doors keep the crap out, as they are closed(including the nose door). we only have one bloke who flies the 210 (the CP), whilst i handle the 185.
cheers,
185skywagon.

[3RAR]

OK, just been talking to a bloke who has a 210 for sale. Still has gear doors and TAS of 165 kts (Verified). The A/C also has a TT of around 2300 hrs. Is it the gear doors, or is it a reasonably low time airframe that give this A/C a pretty strong performance portfolio?

Most 210's that have done more than 5000 hours are nearly sure to have had the mod. Is it because they are clearly used for charter and therefor being flown by several pilots that are the sad result of our sausage factory training system ( a commercial pilot should be able to put gear down while maintaining S&L flight,,,,, one would think) OR, is it the case, that the mod was 'sold' to most 210 owners as the best thing since sliced bread?

I see many arguments for and against, but what I would love to see is statistical data of A/C before and after.

Are there any Owner/ enthusiasts out there that can give me their side of the story?

Also the cost of the mod would be appreciated. ANy of you Kunnas Engineers want to contribute. You guys would have to be the authority on all things 210. Your thoughts would be valued.

OBJ.

[farqueue]

The 210/33x doors are best used as a drag chute! The move to get rid of them came from the number of mixmasters that dug holes while retracting the gear with one engine out. When it was discovered that the door provided no benefit, the 210 system got looked at and the doors went from them as well.

Years ago there was a regular run at ::cough:: MTOW ::cough:: with a 210.The AC could be seen quite clearly to descend while the gear was retracting.

[Continental-520]

Doesn't it usually descend every time you retract the gear on a "cough" MTOW "cough" takeoff? Gear doors or not?


520.