---------------------------------------------------------- Rocket-List Digest Archive --- Total Messages Posted Thu 05/18/06: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:34 AM - Re: Rocket Emp (Jim Anglin) 2. 08:40 AM - Re: Rocket Emp (css nico) 3. 09:08 AM - Re: Rocket Emp (Ron Carter) 4. 07:17 PM - Re: Rocket Emp (J Nelson) ________________________________ Message 1 _____________________________________ Time: 07:34:49 AM PST US From: "Jim Anglin" Subject: Re: Rocket-List: Rocket Emp --> Rocket-List message posted by: "Jim Anglin" As for redesigning important parts like the HS - if you are not an = aeronautical engineer leave it alone. In fact, what makes you think it = is suspect when over 4500 RVs and Rockets are flying with it? Retroing a trim tab is a lot of work when all you have to do is put the = spring loaded trim lever on the stick. I used it in 2 RVs and my HR II = and it works great. I have never heard of anyone balancing this rudder, but see above re = aeronautical engineer. This should be common sense but you are not = alone in trying to re-engineer the most successful, safe, and popular = homebuilt in the world without professional credentials. Jim Anglin HR II N144HR DO NOT ARCHIVE ________________________________ Message 2 _____________________________________ Time: 08:40:58 AM PST US From: "css nico" Subject: Re: Rocket-List: Rocket Emp --> Rocket-List message posted by: "css nico" Good advice. I would hate to see someone change something that causes dynamic loads on something else that might unexpectedly change you from a pilot to a skydiver. Nico ----- Original Message ----- From: "Jim Anglin" Sent: Thursday, May 18, 2006 7:31 AM Subject: Re: Rocket-List: Rocket Emp > --> Rocket-List message posted by: "Jim Anglin" > > As for redesigning important parts like the HS - if you are not an = > aeronautical engineer leave it alone. In fact, what makes you think it = > is suspect when over 4500 RVs and Rockets are flying with it? > > Retroing a trim tab is a lot of work when all you have to do is put the = > spring loaded trim lever on the stick. I used it in 2 RVs and my HR II = > and it works great. > > I have never heard of anyone balancing this rudder, but see above re = > aeronautical engineer. This should be common sense but you are not = > alone in trying to re-engineer the most successful, safe, and popular = > homebuilt in the world without professional credentials. > > > Jim Anglin > HR II N144HR > DO NOT ARCHIVE > > ________________________________ Message 3 _____________________________________ Time: 09:08:28 AM PST US From: "Ron Carter" Subject: Re: Rocket-List: Rocket Emp --> Rocket-List message posted by: "Ron Carter" Hi I have done the first two. See below. ----- Original Message ----- From: "Chris Parkhurst" Sent: Wednesday, May 17, 2006 10:22 PM Subject: Rocket-List: Rocket Emp > --> Rocket-List message posted by: "Chris Parkhurst" > > Gents > > > After 6 years of sporadic effort on my F-1 QB (went to the war, moved, got > married, had a baby..) I am finally looking at the light at the end of the > tunnel and praying that it's not a train! Engine is on, panel is in and the > CP is painted so it's starting to look like something. I built a standard > RV-4 tail about 4 years ago and made the mod per John's plans as well as > added .020 skins. Got a couple of questions that I hope some of you smart > guys can help me out with: > > > 1. Has anyone done any mods to the HS spar? Looks a little light as > designed and have been thinking of adding some sort of doubler at the attach > point. Comments/ideas welcome. No reinforcement of the horizontal spar is required or recommended as far as I know. John Harmon says he has flown his HR2 to 300 mph as I recall. But there has been one tail failure that I know of on an RV-4. Can't comment on build quality in that case. None on a rocket. I dont think thereare any issues with RV-4 tail strength. > 2. My ailerons are built but want to add a small trim tab/servo. > Anyone have any experience with that retrofit? I added elecrtic trim on my ailerons after flying for a year and after they were painted. It is a pretty easy mod. I used 1" wide piano hinge with a servo under the aileron. It works great and is much easier to fly with than the manual type trim. Of course what you really need is an autopilot for those cross countries. > 3. Has anyone done any work with the rudder? Is it possible to > balance? Just a thought ,FYI - Last night I burned a little fuel an was fooling with the rudder- it is very stiff and not very easy to use during normal flight( above 180 mph) there is lots of pedal pressure. But you have to ask yourself, "How much easier do you really want it to be?" As is, the plane will not dutch roll from rudder inpput at normal cruise speeds. You can push on the rudder pretty hard and it just wags it's tail and straightens out within two oscillations, = very stable. The Rocket flies like a rocket- straight and true- it is not a plane designed for heavy gyroscopic style aerobatics. I dont fly mine beyond what Van calls "sportsman" aerobatics and I would start to be concerned about tail strength if I was yawing the plane excessively at high speeds or had the ability to do so. If you havent already, get a copy of 14 years of the RVator and read through the failure modes of the early Vans builders. It will help tremendously on understanding the design and its limitations. Ron Carter HR II #149 558 ttsn > > > Thanks all... > > > Chris > > ________________________________ Message 4 _____________________________________ Time: 07:17:27 PM PST US From: "J Nelson" Subject: RE: Rocket-List: Rocket Emp --> Rocket-List message posted by: "J Nelson" Chris The RV-4 spar is a little light when you look at the negative G.(From turbulence, not acro) During Neg G the horizontal is lifting the tail, and this puts compression forces on the top of the spar. If you look at how this is built, the forward spar is not supported on top and is susceptible to buckling. On the bottom it is supported by the attachments. The easy fix is to put a standard .063 extruded angle doubler across the top away from the vertical fins spar attach and tie it into the ribs. Also the forward spar of the vertical is pretty thin, I beefed mine up by .032 in the area of the bolt holes, and tapered the beef up into the spar about 8 inches. AFT spars seem OK. Ailerons; MAC trim servo is easily added into the aileron, even after it is built. The tab can be built right into the trailing edge, I went one bay out from the root end, and the width to fit between stiffeners and a chord of about 1.75 inches. The servo is up against the forward spar, attaches to the access plat which in turn is screwed on to the top of the skin, flush on the leading edge where the skins overlap already. I did a similar deal for the rudder also but attached the servo to the skin with doublers on the inside, you would need to do this as you built the rudder. As for balancing the rudder; Most don't and seem to not have any issues. I built a mass balance for mine, and balanced about 50%. Peace of mind I suppose, also lightens the rudder forces a bit. My F-1 with RV-4 tail and most HRIIs I have flown, when loaded to an aft CG like with a pax., have some Dutch roll in turbulence, although I have heard the ones with the RV-8 vertical tail do not. I increased the size of my vertical about 4 inches over stock RV-4 and I think it helped the situation but did not totally solve it either. IMO the vertical tail needs to be a bit bigger, and later F-1 kits have a much bigger vertical fin and I have not heard any complaints. Greg Nelson -----Original Message----- From: owner-rocket-list-server@matronics.com [mailto:owner-rocket-list-server@matronics.com] On Behalf Of Chris Parkhurst Sent: Wednesday, May 17, 2006 9:23 PM Subject: Rocket-List: Rocket Emp --> Rocket-List message posted by: "Chris Parkhurst" Gents After 6 years of sporadic effort on my F-1 QB (went to the war, moved, got married, had a baby..) I am finally looking at the light at the end of the tunnel and praying that it's not a train! Engine is on, panel is in and the CP is painted so it's starting to look like something. I built a standard RV-4 tail about 4 years ago and made the mod per John's plans as well as added .020 skins. Got a couple of questions that I hope some of you smart guys can help me out with: 1. Has anyone done any mods to the HS spar? Looks a little light as designed and have been thinking of adding some sort of doubler at the attach point. Comments/ideas welcome. 2. My ailerons are built but want to add a small trim tab/servo. Anyone have any experience with that retrofit? 3. Has anyone done any work with the rudder? Is it possible to balance? Thanks all... Chris