cancidas
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Cessna 525 Question

Thu Sep 04, 2003 10:30 am


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Photo © Tim Lachenmaier



in that picture, the plane has heated wing leading edges, boots on the elevator leading edges, and nothing on the leading egde of the verticle stabilizer. can anyone tell me why there are two different systems used for de-icing on the a/c? also, why is there nothing on the verticle stabilizer?
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m717
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RE: Cessna 525 Question

Thu Sep 04, 2003 10:18 pm

I don't know anything about the anti/de-ice systems on the CJ, but very few aircraft have any anti/de-ice system on the vertical stabilizer. None that I have flown, or can think of off the top of my head.

The Citation Bravo also has two systems. The inboard portion of the wing (that which is directly in front of the engines) uses an electric element to heat the leading edge to prevent ice from forming. This is to help prevent ice ingestion into the engines. The rest of the leading edges of the wings and horizontal stabilizer are de-iced with boots

In general terms, heated leading edges, whether they are heated with electricity or bleed air, are anti-ice systems. They are used to prevent ice from forming. Pneumatic boots are de-ice systems. They are used after ice has formed to remove it.
 
citationjet
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RE: Cessna 525 Question

Fri Sep 05, 2003 2:35 am

To clarify your question, the 525 has de-ice boots on the horizontal tail leading edges, not the elevator leading edges....

The Citation 525 was flight tested with ice shapes on the vertical tail and found that ice does not have an aerodynamic or stability effect on the aircraft; it only increases drag slightly. Therefore the 525 (CJ), 525A (CJ2), and the new 525B (CJ3) being certified do not have ice protection on the vertical tail.

One reason that boots are used on the 525 HT and bleed air on the wings may be engine bleed air capacity limitations to also operate HT anti-ice.

The higher end jets tend to have bleed air & electric. The leading edges are smoother with bleed air compared to de-ice rubber boots. Also rubber boots have more maintenance than "shiney leading edges".

I believe the Model 500 & 550 (Bravo) have VT de-ice boots. However non of the other Citations have VT ice protection.

The new Citation 680 (Sovereign) and Citation X have bleed air on HT and wing.
The Citation 560XL has bleed air wing and boots on HT.
Citation 560 Ultra has electric wing inboard; boots wing outboard and HT.
Citation 560 Encore has electric/bleed air wing and boots on HT.
The 550 Bravo was discussed in a previous posting.

There is another ice protection technology not previously mentioned. The Citation 552 has TKS on the wing and HT. This is basically a fluid the comes out through tiny holes in the leading edge.
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citationjet
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RE: Cessna 525 Question

Fri Sep 05, 2003 3:11 am

Citation 500 - De-ice boots on VT, HT, outboard wing.

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Photo © Christophe Weber


Citation 550 - De-ice boots on VT, HT, outboard wing.

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Photo © Jean-Luc ALTHERR


Citation S550 (S/II) - TKS fluid on wing & HT. (Leading edge polished like bleed air)

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Photo © Henry Lidster


Citation 560 Ultra - boots on wing outboard & HT. Electric wing inboard.

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Photo © Derek Pedley


Citation 560 Encore - Bleed air wing. Boots on HT.

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Photo © Serge Walczak


Citation 560XL - Bleed air wing. Boots on HT.

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Photo © EDDL Photography


Citation X (Ten) - Bleed air wing & HT.

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Photo © CPH Aviation



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L-188
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RE: Cessna 525 Question

Fri Sep 05, 2003 2:21 pm

De-icing boots work by inflating with air and causing the accumlated ice to pop off the leading edge, It is therefore generally considered bad form to place de-icing boots directly in front of say the engine inlet of a jet engine, because of all the ice that will be flying around when they are in operation.

As to why they just didn't go with a straight hot leading edge, I dunno, the capacity of the engines to produce bleed air at low power settings probably is a big factor.

But only somebody who designed the aircraft would be able to give the difinitive answer.
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citationjet
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RE: Cessna 525 Question

Fri Sep 05, 2003 10:03 pm

Many criteria are investigated in deciding between methods for ice protection:

System development costs.
Initial cost of installation.
Maintenance cost of system (boots have to be replaced eventually)
Customer perception (boots may be seen as older technology, "low tech")
Flight regime of aircraft (speed envelope) may affect decision.
Certification issues (bird strike requirements for leading edges)
Bleed air capability of engines
Derivative vs all new aircraft design
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