Saville

Saville

Well Known Member
In looking for my RV-4, I find that no airplane has precisely what I want, which is understandable. Several of the items can be added after the airplane was built but with varying degrees of difficulty and time.

I was wondering if people would comment about the following projects in terms of difficulty and time, assuming a person with moderate tool and electrical skills. I realize that time and difficulty are interrelated.

Time range 1-10 where 1 is a week and 10 is a year

Difficulty 1 - 10 where 1 is easy and 10 is, say, a complete rewiring of the a/c

The projects:

1) Adding navigation and landing lights, and associated switches, to an RV-4 that does not have them.
- running the wiring and being able to fasten them down securely.
- adding switches and circuit breakers assuming there is a place for them (i.e. you don't have to rebuild a panel)


2) Installing long landing gear (and therefore the engine mount) on a short-legged airplane.

3) Installing a C/S prop on an O-320 engine which is capable of swinging a C/S prop (e.g. A1A or any engine that has a hollow crank etc.) but is fitted with an FP.

4) Converting a carburetor engine to FI.


Any insight into the difficulty of these projects would be appreciated. If I had a better idea of what was involved in the upgrades, I might be better able to know which items to compromise on.

Thanks!
 
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Overall this is hard to answer, but I will use 1-10 as the number of full days (8 hrs) to complete.

1) Adding navigation and landing lights, and associated switches, to an RV-4 that does not have them.
- running the wiring and being able to fasten them down securely.
- adding switches and circuit breakers assuming there is a place for them (i.e. you don't have to rebuild a panel)
A: Difficulty probably 3. Time 1-2

2) Installing long landing gear (and therefore the engine mount) on a short-legged airplane.
Difficulty 5-6. Time 7.

3) Installing a C/S prop on an O-320 engine which is capable of swinging a C/S prop (e.g. A1A or any engine that has a hollow crank) but is fitted with an FP.
Difficulty for novice 8-9. Time 3-4, depending on the location of prop governor pad.

4) Converting a carburetor engine to FI.
Difficulty 2-6. Time 2-6 depending on location of fuel pumps and if cylinders have injector nozzle holes already drilled and plugged.


Any insight into the difficulty of these projects would be appreciated. If I had a better idea of what was involved in the upgrades, I might be better able to know which items to compromise on.

Thanks![/QUOTE]
 
I've added a few thoughts below. I am currently building a -4 and have previously built and flown an -8. My -4 will have long legs, C/S prop and FI but its easy for me to incorporate all that. I have run a string through the wings in case I decide I want lights at a later date.

Adding navigation and landing lights, and associated switches, to an RV-4 that does not have them.
- running the wiring and being able to fasten them down securely.
- adding switches and circuit breakers assuming there is a place for them (i.e. you don't have to rebuild a panel)
A: Difficulty probably 3. Time 1-2

Depends on whether the wings have any wiring or conduits already. If there is nothing there, it will be a pain to run the wires through the wing - the fuselage and and wing tip end will be relatively straight-forward. Take off the inspection panel in the bottom of the wing and see how far you can see/reach and think about how you might do it...... Alternatively run the wires in front of the main spar, behind the fuel tank and through the leading edge. That might be an easier route.

2) Installing long landing gear (and therefore the engine mount) on a short-legged airplane.
Difficulty 5-6. Time 7.

But could get worse if you discover problems with the engine mount weldments and firewall or find that the new mount does not match the holes already there......

3) Installing a C/S prop on an O-320 engine which is capable of swinging a C/S prop (e.g. A1A or any engine that has a hollow crank) but is fitted with an FP.
Difficulty for novice 8-9. Time 3-4, depending on the location of prop governor pad.

MMMMMuh. Bolting the prop on is the least of it. You will also need a governer and cable, run to the quadrant or a vernier on the panel, then once everything is installed there is a bit of fiddling to set up the prop so you have the appropriate range of movement, max RPM. I think the crank is plugged and you have to remove or pierce the plug.....

4) Converting a carburetor engine to FI.
Difficulty 2-6. Time 2-6 depending on location of fuel pumps and if cylinders have injector nozzle holes already drilled and plugged.

You will need a new (high pressure) fuel pump and plumbing. You will need to decide if the existing arrangement of fuel tap, gascolator or whatever is to your liking. If it isn't - it will be a good time to change it but adds to the cost and time taken. Andair fuel pump, filter and tap are lovely items of equipment but not cheap!

I think its worth asking yourself -are you really going to fly at night in a single engined airplane??

Why do you want the long legs? Worried about prop strikes? If so is that really an issue with the short legs? It would be worth putting the plane in the level attitude and seeing what the clearance actually is - probably more than you might have thought!

Personally I'd go for number 4 first and then think about numbers 2 and 3. THen likely go for 3. Number 2 I'd need convincing, number 1 - well depends on how you figure risks.

Hope that helps.

Chris
 
People VERY often talk about engines that have a hollow crank and therefore capable of using a C/S prop. There are other considerations. There are a lot of engines with a hollow crank that cannot use a C/S prop. Depends, also on, crankcase, front main bearing style, and accessary cover.
 
Mel said:
People VERY often talk about engines that have a hollow crank and therefore capable of using a C/S prop. There are other considerations. There are a lot of engines with a hollow crank that cannot use a C/S prop. Depends, also on, crankcase, front main bearing style, and accessary cover.
Click to expand...

I understand. My initial entry specified that the engine is capable of handling it...i.e. crankcase, main bearing, and accessory cover are all there for a CS prop.

What I wanted to know was the time, difficulty of the work involved if you had the right engine.
 
Long Gear Legs

Most of early rv-4;s have light wieght motor mount weldments that are often cracked . modifying existing airplanes are often a bucket of worms ,take your time and money estimates double them and add 10 -20 percent
 
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