Quantcast

Firewallon Ridge Runner 3 or other clones

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

WarpedWing

Member
Joined
Jul 17, 2015
Messages
21
Location
Ocala, FL
I have been reading over other posts regarding firewalls and still have not found the answer to my situation. We are building the Ridge Runner 3 (worse documented kit I have ever seen). The manual is worthless and we are getting ready to install the firewall. However, the manual says "nothing" whatsoever about it. Not one word. there is one photo where you can see just a piece of it.

I am hoping that someone here, who built, or is building a ridge runner or one of the clones who might have photos of what they did on their project. Since Yahoo Groups are now defunct, it is almost impossible to find other builders. I will be posting this on the avid forum as well in the hopes someone might be building a skyraider.
 

Victor Bravo

Well-Known Member
Joined
Jul 30, 2014
Messages
7,756
Location
KWHP, Los Angeles CA, USA
So what exactly are you needing to know? The firewall on my Ridge Runner 2 appears (I didn't build it) to be simply a piece of aluminum sandwiched between the forward fuselage and the engine mount. Nothing different than many other airplanes.

It can be aluminum or thin galvanized steel, or even thin stainless steel. It can be sandwiched in place, or perhaps it can be bolted to tabs welded on the frame, or it could even be Adel Clamped (alum. or steel loop clamps) in place I guess.

The firewall on the Ridge Runner (and many many others) is not a primary structural component. It is best described as "semi-structural", in that it supports the cowling, and you don't want the cowling to come loose. But its primary function is to be a safe, tightly sealed heat/flame/smoke barrier between the engine compartment and the passenger cabin.

Although it is not a truly valid excuse from the customer's point of view, the RR3 kit was being produced during a time when the "manufacturer's" family was coming apart at the seams, partnerships and lifelong friendships were embroiled in a major dispute, aircraft design features from one original design were being "borrowed" and used on four or five similar airplanes, etc. etc. Then on top of all that tragic soap opera, few or none of the people involved in this were good technical writers or instruction manual writers.
 
Last edited:

WarpedWing

Member
Joined
Jul 17, 2015
Messages
21
Location
Ocala, FL
Where do I begin? As stated previously, the manual says absolutely nothing about it (as with many other items). My concern has to do with matching the cowling. As I stated there was one photo (actually two after reviewing the manual again) that shows the firewall. In those photos it shows the firewall shaped to match the cowl. Unfortunately there is no template or reference to arc or dimensions required to fitting the firewall anywhere in the plans.

We have not installed our engine yet so I can not fit the cowl and make a rough template myself. I guess I am looking for answers from those who have tackled this problem when building there projects. I would like to get the firewall installed and worry about final fit when we install baffling.
 

TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
13,455
Location
Memphis, TN
Is the cowl complete ready to fly or is it a fit job?
From pictures of finished planes, it looks like the firewall is just a square and the cowl is the nose shape. The side gap has to be open to vent cooling air so it’s meant to have a gap. I don’t think you can do it wrong, do it the way it makes sense.
If they are not giving you an idea, look at pictures of similar planes and adapt. That’s the beauty of a homebuilt.
 

Victor Bravo

Well-Known Member
Joined
Jul 30, 2014
Messages
7,756
Location
KWHP, Los Angeles CA, USA
Mine has a fan cooled 503, and the cooling shroud warm air exits upward through holes in the top cowl. The intake for the fan is parallel and very close to the firewall. So leaving the sides open (stock Ridge Runner, perhaps SkyRaider) would have allowed the air to come in to the cowl, mostly bypass the entry to the fan, then exit out the sides of the cowl. So I sealed up 75% of the side exits, which will serve to pressurize the inside of the cowl, which will hopefully supply more air to the fan. The 20-25% of the side exit area I left open was to allow the flow around the exhaust collector (the Y mounted to the engine) to exit the cowl.

On mine, the firewall itself is square, but there is a half-round "upper firewall" that extends upward to fit inside the cowl.
 

wanttobuild

Well-Known Member
Joined
Jun 13, 2015
Messages
675
Location
kuttawa, ky
WarpedWing
There is a series of books by Tony Bingilis (spell check). They cover basic construction. If I were start over I would start with this series, as they basically cover every aspect.
Ben
HBA's most hated member
 

wsimpso1

Super Moderator
Staff member
Log Member
Joined
Oct 18, 2003
Messages
6,993
Location
Saline Michigan
Drawing on the guidance in a number of books and faced with your situation, I would install an oversized plexiglass sheet in the firewall position, work though all of the details of the engine install including figuring out where everything mounts and where all of the holes go, then rough fit the cowling and trim the perimeter of the firewall, refining as you go to get a perfect fit up. When everything fits, dis-mount the engine and firewall, transfer the shape on the plexiglass to thin stainless or galvanized steel, cut it out, install all the pieces, put it together for good.
 

WarpedWing

Member
Joined
Jul 17, 2015
Messages
21
Location
Ocala, FL
The Plexiglass route is what we came up with also. Just not looking forward to the assemble and disassemble process three or four times.
 

TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
13,455
Location
Memphis, TN
It took me about 40 hours to put together a RV baffle kit for a Lycoming. Beautiful kit. Parts cut, bent, pilot drilled. It would have taken 100 hours if I would have had to do it all. Cowl and un cowl? Probably 30 times.
 

Tiger Tim

Well-Known Member
Joined
Apr 26, 2013
Messages
3,305
Location
Thunder Bay
Just not looking forward to the assemble and disassemble process three or four times.
Plan for more than that.

This cowl I posted is largely fastened with a rolled hinge. When I started fitting the pieces the pins that hold the panels together were a tight enough fit that I had to tap them in with a hammer. By the time I was done they were worn enough from use 4132FE69-7BA6-4AAD-8084-BEEAC7DA9881.jpegthat they slid in and out smoothly as they should...
 

WarpedWing

Member
Joined
Jul 17, 2015
Messages
21
Location
Ocala, FL
Plan for more than that.

This cowl I posted is largely fastened with a rolled hinge. When I started fitting the pieces the pins that hold the panels together were a tight enough fit that I had to tap them in with a hammer. By the time I was done they were worn enough from use View attachment 101730that they slid in and out smoothly as they should...
Now that is a Cowl!
 

Tiger Tim

Well-Known Member
Joined
Apr 26, 2013
Messages
3,305
Location
Thunder Bay
Now that is a Cowl!
Thanks. I can only take credit for finishing it, a lot of effort was put in by a bunch of others to make most of the pieces that went into it. My point remains the same though, there will be a ton of on and off to fit everything well enough to have a job you’ll be satisfied with for years to come.
 

Angusnofangus

Well-Known Member
Joined
Sep 29, 2015
Messages
443
Location
Victoria, Canada
Drawing on the guidance in a number of books and faced with your situation, I would install an oversized plexiglass sheet in the firewall position, work though all of the details of the engine install including figuring out where everything mounts and where all of the holes go, then rough fit the cowling and trim the perimeter of the firewall, refining as you go to get a perfect fit up. When everything fits, dis-mount the engine and firewall, transfer the shape on the plexiglass to thin stainless or galvanized steel, cut it out, install all the pieces, put it together for good.
Excellent advice, but I would use Lexan for a pattern instead of plexiglass. Easier to cut, you don't need special drill bits to avoid cracking, and it is unbreakable.
 
  • Like
Reactions: BJC
Top