AS355 TwinStar
 

AS 355
 

Researching the AS 355 Twin Squirrel and need some background information. Tried various sites with little success. Just a potted history of the aircraft would do. Any clues?

Clue #1. It usually works for me. Go to the website www.eurocopter.com,www.europterusa.com, www.eurocopter.ca, www.eads.net
If you cant find the info there, ask them they usually will send some fancy brochure...
or find a dealer, he may think you want to buy one and take you out to lunch......ha ha

tbc,
McAlpine Helicopters 01865 841188. John Osmond is the man in the marketing dept and will probably be able to help.

AS 355 CG Calculator (Excel)
 

Just polished up the spreadsheet I use for CG - if anyone else wants to use it or maybe improve on it, you can ftp it ftom here:

<a href="ftp://www.electrocution.com/pub/users/electroc/355cg.xls" target="_blank">ftp://www.electrocution.com/pub/users/electroc/355cg.xls</a>

It was done in Excel 2000, and may work elsewhere. The drop down buttons will not work in a Psion <img src="frown.gif" border="0"> . Working on the 206 one!

Cheers

phil

I'll give it a try, thanks very much.. . :)

Email me if you want an explanation of the formulae - we use a system of addendums to the original weighing report here, but the dropdown boxes could easily be used for separate aircraft.

Phil

PS forgot to mention - the top red dot on the graph is the takeoff CG, and the other one represents aafter two hours

[ 24 January 2002: Message edited by: paco ]</p>

:) :) :) :) . .Its very good, thanks very much.

Do you have one for the 109??

No, not yet, as I don't have access to the FM - if you could let me have the relevant details it shouldn't take long to work one up. Working on the 206 right now (with lat CG) and 76 next - just added a dropdown box to change fuel CG according to temperature.

phil

[ 26 January 2002: Message edited by: paco ]</p>

Paco,. .Wow, nice spreadsheet. How did you get the c/g limits set into the sheet?. .Very nice work.

I just used a lot of IF statements allied to a code for the drop down box. The only problem is that Excel only allows 8, so if your company has more than that number in addendums, you have to create a kludge.

I've put all the essential elements in the top left corner, so all you need to do is set the print area and print for a hard copy.

What I want to do next is put in a calculation for Density Altitude and get a red line across the chart with a restricted takeoff weight (no particular reason, just for fun). This is relatively simple to do, were it not for the humidity element.

Would appreciate any "simple" calculations!

Cheers

Phil

[ 14 February 2002: Message edited by: paco ]</p>

As-355f1 / F2
 

My company is planning to add a AS-355F1 or F2 to its fleet.

Does anyone out there have any experience with these helicopters, good or bad!

And what is the difference between the F1 and F2? They both seem to have the C20F engine, so whats the difference.

Any comments appreciated.

355F1
 

The F1 is a fine enough machine, getting a little old these days you may find payload limiting if you require much fuel. New machines are noticeably quicker. Do you like Allison engines, I have no problems with them but many hate them. I have not flown the F2 but don't believe it is much better.
Not enough money for the N or newer gear?
PS. Newer machines versus Allison engine machines..is it just me or are there a worrying number of 135 engine incidents?

Thats just it, we really like the Allison and we definetly cannot afford an 355N.

We have operated JetRangers and LongRanger with little engine trouble so we kinda also want to stay with what we know, but we need a twin to fly N-VFR and IFR.

I have calculated that we should be able to take 2 pax with full fuel and thats exactly what we need.

2 PAX FULL FUEL
 

I guess, IFR fit, 2 pax and full fuel will be about it. If you know the engines it shouldn't take too long to go from American to European engineering thinking. If it will do your job it is certainly a good machine for the money.

F1 v F2?

MTOW is increased on the F2 by letting you have a little more power below about 40 knots. The increase from memory is about 120 kg. The F2 also has the hydraulic over centre accumulator in the yaw channel so you can maintain control if you lose that hydraulic circuit.

OEI it won't matter much as the engines are the same and the F2 can be heavier.

C20F's are the same as a C20 B. Difference is only the gearbox which is very similar if not the same as the B17 turbo prop engine. In fact without a lot of difficulty you can probably mod a B17 to C20F.

If you already have Short Rangers then your maintenance guys will be familiar with the engines. There is a large amount of commonality except for the PTG's.

Depending on the climate the Allisons are prone to oil leaks due to the close cowling of the two engines. Get geared up to change gearbox lip seals regurlarly.

Another unfortunate is the Allisons tendency to have the N2 speed wander around with the met conditions. This doesn't help with keeping the rotor "on speed" where it is smooth. It is also imprtant to try and keep the droop compensation of the two engines similar. Also be sure the engines "top" as they should.

It is possible to fit C20R's but you would have to be brave.

Ice and 355's do not mix. Ask the Brits.

Electrical systems tend to be neglected and are obviously nearly doubled over a single engine Ecureuil.

Your tag indicates Iceland so the OEI performance should be reasonable.

The main advantage of the AS355F2 is an increase in the MTOW from 2400 to 2540 kgs, though the increased weight is only permitted for performance class 2 operations. In association with this there is a hydraulic damper fitted to the tail rotor control system to assist with control of the tail rotor in the event of failure of the right hand hydraulic system below the Vtoss of 40 knots.
Never had a problem with oil leaks or Nr stability. I also never had any problems with icing. The weak point of all the AS355 series is the electrical system, especially in a damp climate. After heavy rain the fire warnings quite often illuminate until such time as the engines have been running for a bit and the system dries out. There is also a problem with moisture getting into the double electrical emergency cut-off switch which can stop you from being able to start up if you shut down in the field and has caused some rather unusual failures in flight, depending on which electrical system you have fitted (and there seem to be a lot of different electrical systems on 355s). Also if, when flying in heavy rain, you leave the forward air vent open, rainwater gets in through it, shorts out the circuit board for the RPM warning system and the horn will come on, causing great alarm until you realise that the Nr are still steady!
Overall though, despite being a bit long in the tooth now, a fine machine with reasonable performance.

From Aesir

Thanks a lot for all the info, it helps a lot. If anyone out there has one for sale send me a e-mail.

We are looking for one with L/H sliding door, cargo hook or provisions, high skids, autopilot & IFR approved. That would be ideal, but if we find one for good price we will simply modify it ourselves.

AS355F1/F2
 

Check with Rogers Helicopters in Fresno, California. The guy to talk to is Robin Rogers. I believe he might be interested in selling one of his 355F1's. www.rogershelicopters.com He also might be able to help you locate one configured the way you want it.

There are a small number of ex-plice AS355s in the UK. All will be high hours but well looked after and keenly priced. The market has taken a dive on these role equipped machines.

For instances there is the one from Western Counties and the one from Merseyside, both recently replaced by EC135s.

If you need contact details drop me an E-mail direct.