The International Cessna 170 Association

Perfect, and then a custom dip stick? Or is there one that goes with it?

As an aside I read story of a French resistance worker who lengthened all of the new dipsticks on Renault trucks being built by the occupying Germans. They went bang for lack of oil. Enjoyed the story whatever the veracity.

I am really struggling with the nosecone. It fits great, but it is too low - i.e. not concentric with the starter ring. The drawing shows a straight line from the boot cowl to the nose cone for the upper cowling, mine has a significant drop in the last 8-10" before the nose cone. I am beginning to wonder whether I should not just fabricate a new upper cowling after I have the nose cone where I need it.

I think what I need to do is stretch the front edge area of the upper cowl to flatten it out, but this is beyond my ability.

Anyone actually done this who has any tips?

daedaluscan wrote:I am really struggling with the nosecone. It fits great, but it is too low - i.e. not concentric with the starter ring. The drawing shows a straight line from the boot cowl to the nose cone for the upper cowling, mine has a significant drop in the last 8-10" before the nose cone. I am beginning to wonder whether I should not just fabricate a new upper cowling after I have the nose cone where I need it.

I think what I need to do is stretch the front edge area of the upper cowl to flatten it out, but this is beyond my ability.

Anyone actually done this who has any tips?

PIcs?

I used Harry Delickers STC and his instructions for the fitment of the cowls. The nose bowl wasn’t going to fit . I rang Harry and spoke to him for hours . This was costing me a heap of money for a overseas call .[Australia-usa] . So I do not have to write a book ,it’s simply that every aircraft is different and you have to use some license in fitment . I used my top cowl as a base line but had to remove about 1.75 ins from the leading edge of the top cowl to have the length of the engine and prop position correctly. The air intake bracket was connected to the carburettor . The nose bowl was then angled to allow fitment intake bracket . [what fun]. Due to my bottom cowl having many repairs and also being cracked it was considered to “repair it” but it was a total replacement. The new bottom cowl started in 3 strips and rolled and then riveted together . Each join has a rivet line has a double row of W spacing of rivets for strength . For the length of the bottom cowl from the joining edge of the nose bowl to the fuselage it was a fit and refit to make the best fit .

Chapter 2 ,
For the engine cooling exhaust air gap on the bottom cowl is a real science and I spent a LOT of time working out the best angle and size for the air spoiler and size of the exhaust air outlet . Spoke to Harry about this issue as there are large cooling thermodynamic /aerodynamic differences of the 2 engines . [continental and lycoming ]. While the new nose bowl has different shape and size intakes the outlet cooling air is just as important . Harry was very vague and non committal when pressed on this area. I have had major cooling issues with no 3 cylinder but now believe it to be fixed. It was a cowl seal blowing down in flight and not sealing correctly.

Note.. the Vans site forum is a good site for learning about internal airflow and cowl modification. My disclaimer is learn about airflow etc not coping their designs .

So this is my first attempt. I put top and bottom cowl on and then added the nosecone. I could not get the nosecone high enough. It fitted beautifully, but the starter ring was about 5/8" above the hole in the nose cone. Too ridgid to budge it more than a tiny amount.

So today I cut the hole for the exhaust and placed the nosecone where I need it to be. I then added the top cowl (in this photo it is just resting there) and screwed it along the boot cowl. This left a gap of 0 at the bootcowl to about 3/4" at the front on both sides. One potential solution is to rivet an external doubler about 1 1/2" wide on both sides of the upper cowl half and drill new holes for the sheet metal screws along its length. The permanent solution will be to remake the top cowl from a new piece of material, completely flat without the drop to the front edge, but I think this may look blocky. In the long term I will probably lose the access door on the left side anyway as I only need it to access the battery now.

AS Ghostflyer says I think these cowls are all a little individual in their own way!! The drawing for the STC shows a straight line from the boot cowl to the top of the nosecone, but I have a distinct roll down to the nosecone in the last 8-10".

Charlie I’m fairly certain the B pressure cowl top half leading edge is a compound curve in all years (down and in). Well I’m certain my 53 is . I think you would go through a fair amount of tin to reproduce it before you would be satisfied with the result.
Two things, It doesn’t look like the composite portion of the cowls have a lip to receive the cowl skins. That would help. Also how much overlap is on the bottom, it almost looks like you need to bring the lower composite portion bottom forward and tilt the top aft but you could only do that if you have enough of an overlap edge at the bottom.

Jim, no lip to locate the cowl, it can slide about freely. I can move it out at the bottom, and do so to ensure it is parallel to the spinner backing plate, lots of material at the bottom lip for this. My only problem is this height issue, and I think my doubler solution will work fine, but may not be the most attractive.

Yes, making a new cowling is daunting. I have a call in to Chris at Delaire who is very helpful so perhaps he will shed some wisdom.

What a demonstration of how {simple a complex job} can turn...or something like that.. (Arrange the words within brackets however you prefer).... I’m glad you’re sharing this Charlie!

Charlie,
Are the split seams in the nose bowl and the top/bottom cowl supposed to line up? I notice the seam on the right is fairly close and the one on the left is way off.

I’d be more inclined to modify the fiberglass nose bowl than the cowl. The cowl determines the overall shape of the airplane, and I think even small changes there would be very noticeable. I’m more of a metal guy than fiberglass, but if Del-Air can’t help with this, there must be a fiberglass craftsman who can.

My hangar co-owner has remade the fiberglass cowl and nosebowl on his home built airplane several times. It’s unpleasant work but the results are really nice.

johneeb wrote:Charlie,
Are the split seams in the nose bowl and the top/bottom cowl supposed to line up? I notice the seam on the right is fairly close and the one on the left is way off.

Thats one of my questions for Delaire. It is so tough that a small change in one area changes everything else. I am going to have another look at all of my engine mounts, and the Lord mounts to double check that the engine is exactly where it should be. Would be a shame to make it fit and then move the engine.

I really hope to avoid modifying cowl - I HATE fibreglass and epoxy resin. Owned too many boats in the past.

daedaluscan wrote:I am going to have another look at all of my engine mounts, and the Lord mounts to double check that the engine is exactly where it should be.

Definitely.

I have an Avcon, but if you need any pics or measurements, let me know.

Retorqued all the Lord mounts with a caliper to get the same "crush" on them all and this dramatically improved things. I think it will go without modifying the cowl.