A new heart for the Predator!

[Vance]

Yesterday was our last flight for a while. We flew to the Cub fly in at Lompoc and had a very nice day.

They had bomb drops and spot landings for 2.5 hours. The spot landing was touch a main down as close to the line as possible without touching down early. They didn’t have to stop and many bounced four times. The wind got up to 17kts steady straight down the runway.

On the way home we flew over Michael Jackson’s Neverland ranch.

Today we pulled the Predator's 135 horsepower O-290G out and planed the installation of the 160 horsepower IO-320B1A.

We managed to disconnect everything before we picked up the engine and everything went smoothly until I couldn’t reach one of the engine bolts because the plug for my strobes is hard up against the bolt. Once again I was reminded what a great job Mark Givans did designing and building the Predator.

I would really like to build a cowl over the engine and create some new fuel tanks. I am trying to keep it simple so that may have to wait until I have completed the installation.

Tomorrow we will begin building new engine mounts and work on the exhaust system.

The exhaust is a challenge in compromise. I am trying to minimize the blockage of air to the prop but I want it quiet and quiet with power means a large muffler. The most logical place for the muffler is right under the starter and alternator but I have long felt that heat is not good for either of these. I want to point the exhaust anywhere but down, it comes out the bottom of the heads so down is easy. The aftermarket systems that are made for a tight cowl pusher are all straight pipes. If I put the muffler in front of the engine, rear on a tractor, it will heat up the fuel injection.

The accessory case appears different and I don’t have a place for an oil filter. I have not found my vernatherm and don’t know where to hook up the oil cooler.

My inlet comes out the back of the sump, front of the sump on a pusher, instead of the bottom so I am hoping to lose some of my prop blockage.

I am also going to try laying the oil cooler down on the keel to have cleaner air to the prop. It is upright now ahead of the prop and has almost a square foot of area. It blocks the tunnel between the landing gear legs. There should be a low pressure area in front of the prop so it should suck and heat likes to go up. I think my air is going through too fast now. The oil cooler is very thin.

She is loaded up on the trailer now with her O-290G laying on the hanger floor stripped of her starter and alternator. The IO-320 is in the back of the truck still without her fuel injection. I weighed the engine without starter, alternator, fuel injection or exhaust and it came in at 245 pounds. I expect the extra stuff to add about 40 pounds.

My new flywheel does not have the correct pitch for the starter so something will have to happen there.

Ed took some pictures and she will post them after she removes a layer or two of oil and grease. I pulled some muscles in my back loading my engine hoist on the trailer so she had to do a lot of the hard work. It was starting to fall on Ed and I did a twisting lift. OOPS. Ouch!

The Van Nuys FSDO says to send him a copy of an aircraft logbook entry on the installation and where I am going to fly off my 5 hours and he will get right back to me with an OK in writing. He was very nice.

I would guess the end of August is an optimistic fly date. That is what I am aiming for. I may miss flying in the Air Show at SMX in August. I want to fly to El Mirage with Ed in the back seat for the Ken Brock Freedom Fly In.

I will try to document the progress. I am not as fast as some on the forum so the postings will be intermittent.

Thank you, Vance

 

[Timchick]

Looking forward to watching your conversion and hearing the end results.

 

[ckurz7000]

Vance, I'm all poised for the posts

-- Chris.

 

[Vance]

Ed ZZZZed out before her pictures downloaded.

She scrubbed down to her sunburn.

Glad to have you along Tim.

I suspect I am expecting too much performance enhancement for such a small change.

I am trying to get some improvement through what I imagine to be aerodynamic enhancements.

As you watch my suffering and expenditures Chris, know that your success was part of the motivation for the change.

You made your cross country look so easy I wanted more altitude and speed capability.

I am hoping that my piloting and planning skills will catch up along the way.

My background and personality makes me want more power in the gyroplane I have rather than just buying a gyroplane like yours and dealing with the registration challenges.

I am off to visit Smokey!

Thank you, Vance

 

[All_In]

Vance very exciting, I'm really looking forward to your pilot reports in regards to performance.

 

[fiveboy]

Vance based on the way you write and the fact that I am some amount of time away from a new engine install (Racer to the rescue!) - I look forward to following your saga.

BTW I have the back of a 97 year old. They wanted to put more hardware in it then is in my Jungle Jet! I have found that by avoiding those twisting lifting or twisting putting heavy things down moves I stay (relatively) pain free. When you carry something make sure you keep the weight in as close to your core (rigid) body as possible and turn your body - NOT your back!

 

[SgurlEd]

Still Removing the Layers... };->

Still Removing the Layers... };->

To Quote Vances Words..."Ed took some pictures and she will post them after she removes a layer or two of oil and grease."

Then to be so exhausted I fell asleep...So sorry to have failed you all last night I was ready to remedy that today only to have Vance in much need of my assistance again he wanted me to photograph the progress while he took the Predator to Smokey's. ( I didn't want to miss an opportunity to photograph Smokey's Deer he has around his place they are pretty cool.)

So I went along and was asked to assist in the set-up and removal of the predator off of the trailer so Smokey could work on her in doors in the coolness of his Garage.

There is a lot of work in order to prepare her to get her on and off of the trailer and with Vances back bothering him how could I refuse my Snooky!

Anyway here are some of the pictures they are the last of our flight in the with O-290G and the Cub Fly-in and also includes our Fly-Over the Neverland Ranch of Micheal Jackson.

The rest are from our Prep work for her to go visit the Good Doctor Smokey who will preform her "Engine Lift" She'll be a spry young thing after her makeover!! The pictures from today are from Smokey's Place and are downloading now.
Photostream:
http://www.flickr.com/photos/94595406@N00/sets/72157621420169612/show
So here we are off on another adventure!
Cheers! Ed

 

[Vance]

Hello John, I am afraid that the fantasy flight date ran into some setbacks today.

Hello Robert, the Predator is so unusual I was afraid that most of what I learned installing the new engine and cleaning up the aerodynamics would not help anyone else. After my meetings with Smokey today I came away with the understanding that it is all applicable in one way or another.

I am going to type something up about today’s progress and setbacks as soon as I finish my banking.

I hope people will share their opinions as the work progresses.

I just saw where Ed posted the pictures from the weekend, nice job sweetheart.

Thank you, Vance

 

[Vance]

Day two of the engine conversion.

Day two of the engine conversion.

Ed and I headed out for Smokey’s shop early with the engineless Predator on the trailer. Smokey lives about 50 miles north of here in Atascadero. As we headed up the steep one lane dirt driveway a green hotrod was coming down. The rotor head was trimming the oak trees as the hot rod pulled almost into the ditch. I squeaked by him by trimming more oaks.

The almost ever present deer weren’t. Neither was Smokey.

I backed up to Smokey’s shop door and got as close as I could. This is always tricky with my monocularity. Smokey’s shop door is just over eight feet high so he was going to have to work on it outside. It was already 85 degrees and the sun was blazing hot.

Smokey showed up about a half hour late and very apologetic. He was waylaid by multiple race car guys.

We unhooked the trailer and slid the engine out the back of the van on to a die table. We made some preliminary measurements and felt the intake is going to have to go through the firewall. The job seemed simple enough until we tried to figure out how to raise the engine into the Predator’s engine bay when it is on the trailer.

After a lot of measuring we determined that the Predator would be 8 feet high with the rotor head and the hat for the rotor head removed. We hadn’t brought the crane with us so it was back to SMX to pick up the crane and remove the rotor head and hat. There are wires that go to the pre-rotator and the rotor tachometer. Mark did a great job of securing the wires so removal went slowly, lots of Adel clamps and lots of nuts and bolts.

While at SMX we stopped by to visit Phil at Coastal Valley aviation and looked at a different Phil’s Cessna 172 that had a similar fuel injection throttle body as the one I am waiting on. Ed made a drawing as I made a lot of measurements. Phil is excited and wants to be kept in the loop. He has taught me how to work on my engine and many aviation mechanic skills. He is an A&P that knows a great deal about all kinds of aircraft and has a room that he refers to as “the dark room” with many treasures. One of them is a digital engine monitor with four exhaust temperature senders that will fit nicely in my panel.

We were back in Atascadero at Smokey’s by 3:00pm. It was very hot as Ed and I sweat to unload the Predator. She slid into the shop just skimming the roof. We rolled her right in front of the swamp cooler. Smokey was so excited that I gave him the whole list of things I would like to do. He had worked in the rain and cold a year and a half ago to finish weld the dual controls so he has a certain amount of trepidation each time I share my fantasy’s about modifying the Predator.

Smokey shared that he found an allure in making something good even better and we went over the list of modifications. Smokey doesn’t want to begin until we have the fuel injection that should have showed up last Friday. I am going to put a tracer on the fuel injection tomorrow.

We discussed a length the value of each of the modifications. He is even more focused than I am on not disrupting the airflow to the prop. We both feel that cleaning up the airframe to reduce drag is the path to higher cruising speed.

He is a great aluminum guy and we both feel that if we start at the end of the front body we can get the tanks inside and have an even taper all the way to the prop. Smokey feels that three separate tanks will work the best, using the central lower tank as a sump for the two side tanks.

We think we found a place for a big enough muffler but we will have to be careful to not cook the fuel injector. Once we get the engine in place we will see if we can get enough volume. Silencing four 80 cubic inch cylinders without losing horsepower takes some volume. By putting it toward the front we end up with a nice taper from underneath up to the prop.

We feel that with properly designed baffles and a nice cowl we will mitigate the Predators overheating challenges.

We designed a front suspension that will have about 20% of the drag of the current ridged front end and have about 5 inches of travel. Smokey wants to make it stronger.

As often happens, the project is expanding and of course that means my fantasy schedule is in the wind. Smokey has enough work to last forever and is working on an all steal 32 Ford Highboy Bonneville Roadster with a 12 cylinder engine that is supposed to run the third week in August. I feel they will be lucky to run it August of 2010 but Smokey will do his best in the meantime.

More to come, Vance

 

[Doug Riley]

Vance:

Way back in the day, Lowell Farrand of Indiana was one of the more successful pioneers in the use of certified engines on gyros. He put a Continental on his (otherwise) stock Bensen B-8M. He was active in the early 70's.

I think it was Lowell who used very long exhaust stacks that led down from the engine to the keel area, then took a 90-deg. turn to discharge horizontally BELOW the prop. This setup was reported at the time to reduce exhuast noise quite a bit, without the need for a muffler as such.

He didn't put a flex-link in these long stacks, but it would be a good idea.

 

[SgurlEd]

Smokeys Place

Smokeys Place

Mornin Everyone!
Here are the Photos from Smokey's Place...
The Deer thought I couldn't see 'em they didn't move not a muscle they actually looked like statues until I moved towards them and then they took off.

Look at this photo...I miss flying already!
I don't know how you folks deal with not flying because of the weather we can fly almost anytime we want now.
Hurry up Smokey and get er done!!

Cheers All! Ed

Ps...Keep your fingers crossed for me the Fair Starts tomorrow and I have 11 entries into the Amateur photo division I could win $7.00 bucks for 1st $5.00 for 2nd and $4.00 for 3rd Place!! If I win there will be no stopping me then...LOL };->
:humble:
Here's the photo Stream from Smokey's Place:

http://www.flickr.com/photos/94595406@N00/sets/72157621298978553/show

 

[All_In]

Keep us informed...

Good luck Ed!!!

 

[Vance]

Thank you Doug,

That is just the kind of input I would like to have.

I thought about going down to the keel with the exhaust for two reasons.

I don’t like running the exhaust into the prop because of heat damage to the prop and noise.

Tubes running parallel to the airstream don’t have much drag.

Weight is one reason not to. Even a very thin exhaust is heavy if it is long.

I couldn’t get down to the keel without having a length of round tube exposed to the wind at right angles where the coefficient of drag is 1.2.

The predator has a lower structure made of tubing that is smaller than any exhaust tube and I am hoping to make streamline pants for the two sides. The exhaust would be at the rear where it is the thinnest so if I ran the exhaust down to the keel I would lose any advantage that I gained from the pants. I am going to move the oil cooler from this tunnel for the same reason. I want the prop to see as clean air as possible.

Exhaust silencing is very complex so I have chosen a simple path. Run all of the pipes into a box that has a volume that is some multiple of the single cylinder displacement with an exit that is slightly smaller than a single pipe going in and you have a back pressure muffler. The larger the volume the less it impacts the performance and the quieter it can be.

Larger is heavier and in the way aerodynamically.

Mufflers also get hot and radiate that heat in all directions so the muffler needs to be well clear of the fuel injection and electrical components. The fuel injection on the IO-320 is well known for not managing hot starts well. On the other hand, Piper ran a muffler at the back of the engine, front on a pusher, near the fuel injection for a long time and Piper seemed more focused on a good exhaust that most of the other aircraft manufactures.

At this stage of the design process we feel we can get a fairly large oval muffler at the front of the engine hidden from the wind above the floor of the cowl and clear enough of the fuel injection. The cowl will taper up toward the prop so we don’t have this room at the back. The sump is in the way in the middle.

We will know more once we have the engine mounted.

It is all about compromise. Smaller is either louder or more restrictive. Bigger is heavier and more likely to heat something up or get in the wind. Down is louder for the people on the ground rearward is louder for the people on board because it reflects off the prop.

I can no longer hammer or gas weld aluminum well so I am going to have to get Smokey to make all these bits. It is never easy to get his attention.

The goal is a 90kt cruse at gross weight. The rotor takes care of itself as the speed goes up. I hope to reduce the drag of the aircraft by 30%. Most of the people around here think I am being silly trying to reduce the drag of the Predator because gyroplanes don’t go fast anyway.

Most of the people around here also feel that loud is good so they are laughing at my efforts to quiet the “music”. They fly at 7,000 feet and above so they only annoy people when they take off. They want to attract attention when they are taking off. Some of the people I am trying not to annoy are onboard the aircraft. I love the sound of the rotor and when the engine is loud it masks the sound of the rotor and the wind that I love so much. My ANR head set helps but I want more.

I love this stuff, thank you, Vance

 

[barnstorm2]

that last photo makes me feel unbalanced.

I felt like I needed to grab the cyclic and straighten us out!

I love the shot! Keep posting!

Good luck on the contest!!

.

 

[StanFoster]

Vance- This is interesting as it gets. I know you are an achiever, so there is no doubt of the outcome. You cleaning up the aerodynamics will boost your speed a knot at a time. Your explanations of clean air....and mufflers.....heat....etc. make this a nice thread to learn from. Th average IQ of this forum goes up when you post and we read. Stan

 

[RotoPlane]

I enjoy seeing drag destroyed.

I enjoy a quiet exhaust.

I enjoy the high performance more power (insert a "Tim the Toolman Taylor" howl) can bring.

That's why I too am enjoying this thread!

 

[GyroDoug]

I love the sound of the rotor and when the engine is loud it masks the sound of the rotor and the wind that I love so much. My ANR head set helps but I want more.
I love this stuff, thank you, Vance

I agree Vance!!!

I really want to make mine as quiet as is reasonably possible so I hear the rotors more. I was watching Mike Brownlee fly his Butterfly Aurora on Saturday with a Rotax 912S engine. There was also a fixed wing piper flying in the same pattern and it was amazing how much louder the Piper was than his Aurora with the Rotax 912. It even had very minimal mufflers and was a lot quieter, so I am thinking once I run my exhaust through a turbo it should really be pretty quiet. I can't wait to hear it run.

Keep up the posting on your upgrades. You are an inspiration to us all.

Gyro Doug

 

[okikuma]

Hey Vance,

Remember when I showed you the exhaust pipes on Sammy Mason's Fourner RF4 motorglider at KSZP? The rear of the exhaust pipe was tapered closed at the end and there were multiple holes drilled in a row on the side of the same, facing perpendicular to the airflow. Those holes produce enough back pressure required while at the same time effectively reduce the exhaust noise without the added weight of a muffler.

In my mind's eye, I can visualize you creating a 4 to 1 tuned exhaust header for the O-320, then running a single exhaust pipe down and along one side of the lower keel, below the prop, with the exhaust gases exiting past the prop to the side.

The number of drilled holes times the area of each hole can be made greater to, equal to, or less than the total area of the hole in a straight exhaust pipe.

Wayne

 

[helipaddy]

Vance,
Here's a link to the exhaust type that Wayne is talking about. It seems to work quite well.

http://shop.airworlduk.com/the-ilmer-silencer-for-airworld-exhaust-systems-300817-891-p.asp

 

[okikuma]

Very close Paddy! The Fourner RF4 motorglider only had one row of holes, but the example you provided does suffice nicely. Thanks!

Vance, as I think about it more, perhaps you could make several examples with different number of holes, hole diameters, and lengths so you could test each one by sliding each on and off to compare for best noise reduction.

Wayne