P

pilot28906

Well Known Member
I will soon need to order the finish kit for the 7 and according to the form need to make some decisions. Problem is I do not have an engine and will probably go with a mid-time engine or rebuild so the exact engine is unknown. I know I want a 180 HP 360 parallel engine with no more than 8.5:1 comp. ratio and will be using FP prop. Things that are unkown but are on the form are:
1)Vertical or Horizontal induction (which is more common on used engines)?
2)Dynafocal 1, 2, or Conical (again which is most common)?
3) Fuel Injected or Carb. This is a never ending internal debate with me and I would not pass up an engine based on either if it was a good buy when needed.

Which above decisions are easy to change down the road and which are costly and time consuming?

Any advice appreciated.

Thanks
 
My thoughts but I am no expert on any of the topics.

#1:
I would think you want horizontal so you can take advantage of ram air to increased performance.

-------------------------
My understanding of #2 is that you want Dynafocal.

Here is some more reading on the difference between 1 and 2, as well, but seems to contradict itself. Sounds like you want type 2 if going with fuel injection (IO vs O).

http://www.experimentalaircraft.info/articles/aircraft-engine-mounts.php

Excerpt from above site:

Conical mounts
This is by far the easiest mount to fabricate. It has four attach points for the engine and usually four points to bolt the mount to the firewall. The mount points are parallel with the firewall, so there is no awkward angle when installing the bolts and shock mounts to the engine. Its all rather straight forward and really easy to do.

A drawback is that vibrations and engine torque are transmitted through the frame so this is not ideal compared to a dynafocal mount.

Dynafocal mounts
These are the best and do a perfect job of cushioning the vibrations and movements from the engine. Lower cockpit noise is the result with less pilot/crew fatigue. One drawback is that they are more difficult (expensive) to build / construct and install. As you can see from the image the engine is held in four attach points (located in a ring) and these are under a certain angle and point to the center of gravity of the engine.

During welding this angle must be held in perfect alignment or else the four bolts will not fit when installing the engine in the mount.

Type 1 or 2
There are two types of dynafocal mounts: nr.1 and nr.2. Type 1 is used to Lycoming engines up to 180 hp and the type 2 is used in the IO-320 and IO-360 model engines from Lycoming.

-------------------------
#3:
Go with fuel injected, if you can. No carb heat to deal with and better fuel burn/economy. It costs more up front but that carb will eventually need to be rebuilt. With the savings in fuel, and overhauls, injection should pay for itself.
 
I am hoping to find a good used IO-360 in need of rebuild. A friend and RV-8 owner/builder is very familiar/experienced these engines and has offered to assist. He picked his up in similar fashion and, if I recall, has around 15k invested and pushing close to 200 HP.

He is also the one that suggested I avoid the conical type block.

In any case, I need to finish the fuselage before spending any more cash!

When we finish, we'll have to meet up. I have property in Franklin, just up the road from you, near the Macon Co. airport (1A5). Hoping to shorten the trip from 6.5 hrs to under 2 :)
 
Thanks again. Let me know how the engine hunt goes. Yes Franklin is just over the mountain. I fly out of KRHP. Hope to see you some time.
 
There are sooo many things wrong with that experimentalaircraftinfo listing.
please ignore it.

Plan for type 1 dynafocal. Has nothing to do with engine size. Type 2 is from particular twins with long prop extensions.

max future flexibility will be via cowl with snout for vertical induction. If you want a smooth bottom cowl for horizontal induction it is your choice but it will limit the engine options and cost more to finish because of the higher cost of horizontal intake and fuel injection.
 
Thanks Ray and Bill. This was the advice I was looking for; max flexability. Thanks Bill for clarifying the mount type.

Either of you know why Van's needs to know if you are using carb or FI for the finish kit. I am assuming a carb or FI can be used with the vertical induction and snout on the cowl?

Thanks again. :D
 
John,
It's all about which of the two cowls. In Van'sese, fuel injection means no snout.
Buy the carb cowl.
 
John,
It's all about which of the two cowls. In Van'sese, fuel injection means no snout.
Buy the carb cowl.
 
You must log in or register to reply here.