Need advice on RV-4 kit order form

I am about to order my kit and have a few questions.
I plan to build it light, the lightest possibile, provided that I will probably install an IO-360 (so I may go with a MT C/S prop).

I sent an email to Van's and the only advice they gave to me is to change the 0.016'' tail skins with 0.020'' ones.

I will also like to keep it also very simple in order to save building time.

So, I will go with:
- electric elevator trim;
- prefabricated phlogiston spars;
- float fuel sending units (very accurate on my -9 Dynon equipped; don't want to change);
- manual aileron trim.

What about electric flaps? In my -9A the arm and the motor weight a few pounds. Is the manual flap option lighter than the electric one?

Thanks.
Camillo

Think about your mission. If you will fly with people in the back seat, you will have to de-conflict with them every time you deploy or retract the flaps. The flap handle ends up between your left hip and the passenger?s left foot. The weight difference would be approx 3 pounds.

What I did

I have a basic and light VFR -4, and almost always have a backseater. I can advise the electric flaps are great,and dont get in passengers way. I have electric elevator and aileron trim and it is really nice. My flaps and trim are all on the MAC stick grip, so I never have to take a hand off for trim or flaps..that is a great thing if its turbulent. These are all easy options while building, but a bit difficult to retrofit later. Aileron trim is really handy on these birds if you dont want to keep switching tanks.

3 pounds extra for electric flaps, I suppose.
However, you all suggest for electric...
Thanks.
Camillo

Suggestions

Cammilo,

Food for thought.... If I were to build a 4 again and I am very tempted to..... I would build it as a fastback. Check out some photos of fastback 4's they look great and are probably a bit faster than stock. I would also consider a Rocket front end but keep the stock 4 wings.

One of the best places you can save weight is in the panel but there are lots of other places too.

Electric trim and flaps are good.

Hi Camillo, sorry not to reply to your email earlier but I was 15 hours a day doing my ski instructor exams not so far N of your Northern border in Austria. Working hard at 9000' every day left me exhausted.

So you have read my blog, and I am not sure what else to add.

Some say you dont need them, but I would go for the heavier elevator skins. As you said VANS reccomended them. Also plan on an Odyssey battery but that is obvious. I would certainly go for the electric flaps and I think the mechanism must surely be lighter. There is an ergonomic problem I am told with the manual. What else? You say an -360. VANS will tell you the aircraft is designed for 150hp. With a -320 it has 160hp. Quite why one would put in 180+ I am not sure. Yes it will go a little faster and climb a little faster but does that really make you happy. Similarly IO or O. Yes the cht egt graphs are not as pretty with O, but Lycos have been running on carbs for years and its simple and works, cheaper lighter etc.. I can run all cyls LOP.

Yes I have an MT prop but that was primarily because my old strip was only 1000', and going into that with a tailwind I needed all the help I could get stopping. Otherwise the cost complexity is not justified though I have to say its nice and makes for very smooth cruising. Compared with a FP prop its heavy but the -4 does need weight forward for the day you take a PAX.

PMAGS are light, and you can save a huge aount in the panel by using electric instruments, EFIS etc. I would throw most of the wire and switches out also. I got it down to 6. They are, from L > R

1. Master / Alternator
2.Strobe / Starter
3. Fuel (LH side of panel)
4. Flaps.
5&^ are the P-mags on the RHS

Then on the stick there are 3:Trim, PTT and AP disengage.

Yes OK there are two other switches for seat heaters but they are on the sidewall, and nothing to do with flying. The rest is the normal switches for each instrument. I then use one of those auto fuse holders they weigh nothing

So, KEEP IT SIMPLE.

Camilo, feel free to come back to me by email if you want to discuss more, but I thought I would put this here since it may interest others.

Camillo, one more thought.

I very nearly went for the oil cooler that Porsche use. Its a Swedish thing but I cant remember its name. The O-320 overcools badly and the great big thing I have weighs a ton, and thats before you fill it with oil! A smaller unit would fit much more easily

And then the starter. I used the flyweight but starting the engine it distorted and I had to go up a grade. Read here. The new one is fine, light, but not as light as the first.

Cheers!

Tanks

I think a great modification in the -4 is to add fuel capacity through the use of Rv-6 or Rocket tanks. If you build the wings this way from the start, you won't add structural weight, but you will add a great deal of utility, especially with a larger engine.

The stock 32 gallons really limits range, especially if you like to land with 1 hour of fuel reserve.

The only downside is that you have to keep a closer eye on staying under gross weight when you carry a passenger with full tanks. I think the benefit far outweighs this disadvantage (unless you always fly in the pattern and are terrible at math).

M

Long tanks

I agree with M...I would have done this if I knew what I didnt know! More fuel could be better, as I have found doing fly-outs to places that dont sell fuel. Just another 12 gallons would be great. With a backseater and any baggage, its better with fuel for CG anyway.

Steve, thank-you very much.

I am convincing that the -320 will be better than -360.

Why IO? Because I do have problems with my RV9A to reach the cylinder peak: it starts being rough well before. And I would like to eliminate the need of a carburetor heat. Also, I would like to be capable flying inverted.

I am planning on very basic instruments:
- Dynon SkyView (which I have on my 9 and I am very happy);
- battery backup;
- Dynon transponder (weights 1.5 Kg. less than Garmin 328);
- ICOM radio;
- GPS 296.
Maybe an analogic G-meter.
That's all. No lighting, no backup instruments, no VOR, DME, ADF ot other stuff (I have all on my -9 and will do travels with it).
Fuses instead of CBs.
Panel switches for battery, alternator, flaps and fuel pump.
Stick switches for elevator trim.

Of course an Odyssey battery.
Permanent magnet Bandc SD-20 alternator.
Skytech starter (it's OK on my O-320).
Electric flaps.

Have to investigate on Setrab cooler, PMAGs and -6 tanks. Do -6 tanks fit the -4 wing or do I have to make some metal working?

Already received from Van's an answer about upgrading with 0.020'' tail skins. No input on other changes from Van's (e.g.: forward fuselage 0.040'' skins).

Thanks.
Camillo

M and Bill, thanks.
Could you please tell me more about upgrading tanks? Do I need to make metal working to fit -6 tanks on -4?

Tanks

Extending the tanks of the -4 is not a big deal if you do it during construction of the wing.

I suggest looking at a set of RV6 wing plans and comparing them to the -4 with regard to tank installation. The -6 tanks are longer, but they are constructed and mounted in exactly the same manner as the -4.

If you want even more capacity, look into Harmon Rocket tanks. I believe John Harmon can provide detailed installation information for you if you go that route.

This topic has been discussed in more detail elsewhere in the forum, so you might want to search around a bit. Good luck!

M

I read it.
If I go with an (I)O-320 I will have 1/2 hour less endurance than that with my 9A. Not a big deal, since this will be my second, sports, airplane.