harrystanhope
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Helicopter Retractable Undercarriage

Fri Aug 16, 2013 6:31 am

Obviously retracting the undercarriage has advantages to all aircraft but I was wondering why some helicopters have them..

For a fixed wing it seems to make more sense to me seeing as they usually travel further, have less moving parts than a helicopter and can help slow the aircraft down...but would having retractable gear make all that much of a difference to a helicopter? Or is it more of an appeal to have wheels that come up? The Augusta 109 looks very slick with wheels up  
 
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Starlionblue
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RE: Helicopter Retractable Undercarriage

Fri Aug 16, 2013 7:36 am

Retractable undercarriage makes a significant difference in drag and fuel burn even in general aviation planes doing 120-140 knots. Even spats on the wheels will give you a percent or two.

Many helicopters routinely exceed those speeds so retracting the undercarriage makes sense.

[Edited 2013-08-16 00:36:40]
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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CrimsonNL
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RE: Helicopter Retractable Undercarriage

Fri Aug 16, 2013 7:02 pm

Quoting HarryStanhope (Thread starter):
The Augusta 109 looks very slick with wheels up

Not nearly as good as the Bell 222!


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Martijn
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Starlionblue
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RE: Helicopter Retractable Undercarriage

Fri Aug 16, 2013 8:16 pm

Quoting CrimsonNL (Reply 2):
Not nearly as good as the Bell 222!

  

"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
dw747400
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RE: Helicopter Retractable Undercarriage

Sat Aug 17, 2013 12:04 am

The Bell 430 comes in both a skid and retractable gear version; retractable gear gives about a 10 knot boost in speed at normal cruise power. Not trivial, but not enough to justify the added cost and weight if you are doing short hops. Many folks seem to think the retractable gear on the 430 was mainly an effort to appeal to the corporate market.

Faster helicopters, like 109s and S76s likely derive a greater benefit from retractable gear.
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citation501sp
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RE: Helicopter Retractable Undercarriage

Sat Aug 17, 2013 3:29 pm


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The S-76! All slicked up and moving.

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Max Q
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RE: Helicopter Retractable Undercarriage

Sat Aug 24, 2013 5:54 am

The S76 is so beautiful it could almost persuade me to leave fixed wing..
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tjwgrr
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RE: Helicopter Retractable Undercarriage

Tue Aug 27, 2013 4:38 pm

One of my favorite local RG 'copters.... an EC155 sporting maize and blue.....

http://www.helis.com/h/ec155_n155um.jpg
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An225
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RE: Helicopter Retractable Undercarriage

Tue Aug 27, 2013 5:54 pm

In some cases, operators who have helicopters with retractable gear prefer to keep them locked down for MX reasons as well as boosting safety.
For example, the IAF operates their CH-56's with wheels down all the time.

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AF1624
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RE: Helicopter Retractable Undercarriage

Wed Aug 28, 2013 10:22 am

Also, I imagine although there is a big gain from having a RG helicopter in terms of drag reduction - you have to consider the fact the RG system itself is a lot heavier than having just skids.

So I guess there's some balancing there somewhere to be done, there must be a break even point where the advantage of the drag reduction outweighs the advantage of having very light skids instead of a gear retraction mechanism.
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