ICP Savannah/MXP740 questions and picture judging

[Pat]

Curious for your advice on the below pictures.

 

What could be the reason for this different, longer bolt? 
 

Should I secure these bolts with loctite? 
What is a suitable grease for the bolts that hold moving parts (ailerons, flaps, elevator, rudder)? 

 

Any concerns for the strut attachment plates? 
 

 

Repair ideas for this one? Rivet a doubler s sheet? 
 

Where do you buy these camlocks? 

 

BRS cover is made of thin plywood. Any recommendations for a more suitable material? Plastic? Thin sheet aluminum? 
 

Thanks for the help! 

Pat 

Edited August 11, 2023 by Pat
typos

[Pat]

I didn’t intend to post the pictures of the rubber grommets for brake/fuel lines and gas caps but since they’re there I might as well ask: Any source to buy replacements? 

[pluessy]

I would recommend to remove the strut brackets, strip the paint and crack test them. This looks like cracking has started at the gussets:

 

For the chute cover, make a new plywood sheet, seal it with thinned epoxy and add some foam to the underside with 1 layer of G40 glass. The cover needs to be able to be blown off easily when activating the chute.

 

[Kenlsa]

Those strut bolts in the first picture don’t look like AN bolts.  If not they are not airworthy. Don’t use grease or Loctite on any nut or bold particularly nylon nuts.

[IBob]

The extended nut in the first pic was maybe used to mount a camera or similar?
The bolts should be secured with the correct AN locknuts, not Loctite.
The current maintenance manual calls for quote: white grease, Renolit Z2 for hinges/bushings/bearings/rotating parts. It also calls for Bardahl High Speed chain spray grease for rotating parts and general additional lubrication.

 

I would definitely be inspecting the strut attachment brackets, as suggested by Pluesssy (above).
I would also be checking if the bolts are of the correct type, as suggested by Kenlsa (above). I believe they should all be AN hex head, with matching washers and locknuts, not socket head, and that includes the bolts through the struts. It would be interesting to know why the socket head bolts have been used???
It is this stuff that holds the wings on...........................

 

No comment on the crack, trying to figure out where on the aircraft this is and what it does?
Camlocks are from Aircraft Spruce, get the dimensions and search online for the correct part #.
Grommets are any auto/hardware supply.

 

[old man emu]

Camlocs can be obtained from any of the major aircraft hardware suppliers. Here is the spec sheet for them

 

 

What could be the reason for this different, longer bolt? More than likely it was used to attached something like a video camera. The bolt itself is probably not long. It is the long nut that is fooling you.

 

Repair ideas for this one? Rivet a doubler sheet? Either buy a new panel or get the drawing and material specs and make a new one. Making a new one is quite OK if you have the  data. The job comes under the approvals for MITCOM - Manufacture in the Course of Maintenance. Just make sure that an entry is made in the aircraft's logbook that shows the source of the data and materials.

 

Any concerns for the strut attachment plates?  Not if you get a bucket of paintstripper to expose the seams, and have the welds checked for cracking.

 

BRS cover is made of thin plywood. Any recommendations for a more suitable material? Contact the manufacturer of the BRS to find out what material can be used. I think aluminium or plastic would be too stiff and would prevent the BRS from exiting the fuselage if required.

 

Rubber grommets  You're a wealthy aircraft owner. Splurge a few Euro on new grommets.

[Marty_d]

Check the BRS website.  When I was considering putting one on the recommended cover was light polycarb or similar, with a circle scored in it and radiuses scored from the centre out in 45 degree increments.  

The intention being that if the rocket fired it'd break through the scored polycarb and those radii would open up like a flower.

I agree with the others re strut mounts and bolt types.  Not a huge investment to replace all the essential (wing-holding-on and primary control) bolts with proper AN ones, and you'll get peace of mind.  Definitely need to take the paint off those strut mounts and check for cracks though.

 

What is the part with the crack in the side where you asked if a doubler should be used?  If at all important I would fabricate a new one - doesn't look very big but the rolled edge may give you trouble. 

[Pat]

Thank you all for the helpful replies!

 

Any suggestions for a paint remover? Is it ok to initially leave the wing strut attachm. plates in place and expose (strip paint off) only the seams? Or better remove the plates and only the strip the paint? 

 

I will have the nuts and bolts replaced to AN spec. Apart from ICP, is there a good source for these? 

 

I have emailed ICP regarding the strut to fuselage attachment plates and they replied

 

"The wing strut attachment are not ICP." 

 

Not yet sure what to make of that reply. Browsing some fotos of other MXP740/ICP Savannah planes online I found show very similar looking wing attachment plates, however I could be wriong.

 

There was an AD in 2005 based on a SB from ICP, I saw it somewhere in my plane's records as well. 

 

Manufacturer's announcement: SERVICE BULLETIN 02-2005 from I.C.P. Srl

Structural failure

Affected series: all

Affected work numbers: all

Occasion:

Accident of an aircraft of the Savannah model in Norway due to breakage of the mounting plate wing main spar to the front strut

Measures:

Checking the condition of the attachment of the front strut to the wings according to the

Service bulletin of the manufacturer.

Dates and deadlines:

The measure must be carried out before the next start.

 

 

 

 

 

[IBob]

My understanding is that ICP were originally agents for a S American derivative of the Zenith 701.
They then began to manufacture their own version.

So, maybe what you have there is a S American model?
Either that or it has been damaged and someone has made replacements.

 

It's interesting also that the aircraft is painted but the struts are not.
 

See attached pics for ICP strut attachment. AN bolts down the sides, A4 rivets across the top.

It is also AN bolted at front and back inside the undercarriage tunnel. So the main undercarriage would have to come off to remove the attachment.

Given the critical function of the assembly and the use of nonstandard bolts, I think I would be removing them to verify that they are free of cracks throughout. This would include the bolted flanges inside the tunnel.

I would also be checking all wing attachments for correct bolts.

The AD you refer to is for the front strut attachment at the wing main spar (not at the fuselage).

 

[Pat]

Thank you for pointing out my AD misunderstanding.

 

ICP says the parts for my plane were manually cut ("hand built") vs. later models that were cut using CNC. 

[Pat]

On 12/8/2023 at 6:57 AM, Marty_d said:

What is the part with the crack in the side where you asked if a doubler should be used?  If at all important I would fabricate a new one - doesn't look very big but the rolled edge may give you trouble. 

Intake air scoop on the back/top of the plane. Not a structurally critical part, I think. 

[Pat]

Does anyone know why some Savs have these additional strut links, and some don't? 

[IBob]

Jury strut. To prevent the strut from buckling under negative Gs (including when landing).
The earlier Savs did not have them, the later ones all do. I guess they decided it's a good idea (despite the struts being quite rigid) and especially once they added the optional extra tanks, which carry twice as much fuel in the wings.

 

Very easily added if you wish: they are held in place by 3 rivets into a wing rib at the top, and a band that fastens round the strut at the bottom.

Edited October 23, 2023 by IBob

[Pat]

Thank you, very interesting. 

[Pat]

80 hp performs quite well https://www.flysto.net/logs/10dxglyk/departures/0?view=video 

 

[Pat]

My Savannah Rotax installation does not carb heat. The air cooler inlet scoop and cooling screen is behind the cabin. Is carb ice not a factor? Or why omit carb heat? 

[Pat]

Cheap but nice "upgrade". Velcro doorpanel storage nets from Tasmanian Tiger (10€) added to my Savannah. 

[IBob]

29 minutes ago, Pat said:

My Savannah Rotax installation does not carb heat. The air cooler inlet scoop and cooling screen is behind the cabin. Is carb ice not a factor? Or why omit carb heat? 

 

Yes, absolutely, carb ice can be a problem.

Some Rotax equipped aircraft do not have carb heat, but instead take air from under the cowls all the time.
A VG on our airfield does have carb heat, and the XL and S Savannahs all do too.

 

It's probably easiest to post a pic of what you have under the cowl, Pat?

[Pat]

8 minutes ago, IBob said:

 

Yes, absolutely, carb ice can be a problem.

Some Rotax equipped aircraft do not have carb heat, but instead take air from under the cowls all the time.
A VG on our airfield does have carb heat, and the XL and S Savannahs all do too.

 

It's probably easiest to post a pic of what you have under the cowl, Pat?

 

[IBob]

Yep, that's the arrangement on at least one of our club Tecnams, and I'm not aware that they have icing problems, apart from one possible incident some years ago.

How effective it is will depend on what sort of temperatures you get at the air intakes under the cowl.

Probably best to avoid long descents at low power settings?

[Pat]

Thanks Bob, can you please elaborate on "the arrangement". Eager to learn. 

Just a little add on: I recently read, contrary to my experience and what I was taught so far (low power = carb heat on) that acc. to physics the low pressure (and subsequently the cold temp in the carb) is highest at high power settings. 

Anyway, is the engine compartment of my Savannah sufficiently warm enough to avoid carb ice? 

[IBob]

Pat, what I meant by 'the arrangement' is the individual air filters on the carbs, taking air always from under the cowl, which should be warmer than outside air.

And my suggestion about sustained low power settings (usually on long descents) was because the engine will be producing much less heat in that mode of flight, so the air under the cowl and entering the carbs will be cooler.
I cannot say if your engine compartment is warm enough to avoid ice. That depends very much on how the air circulates there. I suggest your best source of information would be from pilots operating similar aircraft in your climate.

[perrynz]

Hi Pat. Just to add my two cents worth, as others have mentioned, the hex headed bolts and nuts need to be swapped out with the correct AN hardware. The bolts that are fitted in your plane appear to be stainless steel, and are unlikely to meet the same tensile and shear strength as AN bolts and nuts. Additionally, the threads on aircraft bolts are formed by a rolling process (not cutting) and are therefore much stronger in tension applications. Looks like a great project ahead of you. Cheers. Perry

Edited December 27, 2023 by perrynz

[Pat]

2 minutes ago, perrynz said:

Hi Pat. Just to add my two cents worth, as others have mentioned, the hex headed bolts and nuts need to be swapped out with the correct AN hardware. The bolts that are fitted in your plane appear to be stainless steel, and are unlikely to meet the same tensile and shear strength as AN bolts and nuts. Additionally, the threads on aircraft bolts are formed by a rolling process (not cutting) and are therefore much stronger in tension applications. Looks like a great project ahead of you. Cheers. Perry

Thanks, those will be changed. I've been in touch with ICP Italy regarding ordering a set of AN scres/bolts/nuts and have sent more than a few emails the last months... "tecnico" is helpful and always replies "I will forward to sales" but I never get any reply from sales 😕

 

[Blueadventures]

3 hours ago, Pat said:

My Savannah Rotax installation does not carb heat. The air cooler inlet scoop and cooling screen is behind the cabin. Is carb ice not a factor? Or why omit carb heat? 

You can buy electric carb heat devices from Xair in Ireland.  I fitted these to my 912 in a Nynja. Best to have and use carb heat. Had a carb ice experience on another 912 UL aircraft, not fun and don’t want ever again.