Randi Flys His Merlin Taildragger! And an update on Frank’s Merlin Build

Great idea for installing the wings without a helper.

Randi has the only Merlin taildragger in USA and recently finished and flew it. I will ask him for his impressions.

Here are some of his build comments:

Have ~0.7 on engine in taxi tests, am very happy with engine all the temps look good. have prop adjusted (30 degrees, started 20, then 25) static RPM is just below redline as is highspeed tail high taxi. Laser checked engine RPM and it agrees with EMS (less gear reduction).

Changed out tailwheel to a pneumatic scooter wheel, like it much better doesn’t sound like I am dragging a bunch of cans behind me anymore. Confirmed all the weight and balance calculations, leveled the plane and laser plumb-bobbed all the datum points, tailwheel dimension changed a tiny bit due to the replacement  fiberglass spring but everything else agreed.

Mowed the grass runway, Merlin likes grass much better than asphalt, is a tad squirrel like with highspeed (40mph) taxi but then it wanted to fly and any tail wheel is a handful high speed taxi part of it is me getting accustomed to that brake system. I am wearing dive booties so I can feel the rudder pedals  May end up with a extension to the brake pedals off to one side so you slide up and on it like a heel brake, will see. Had a week full of virtual meetings, an annual convention but it wrapped up today so can play. I am guessing it will fly Friday morning weather permitting, for sure over the weekend.


Note: Randi got to play early and flew on Thursday.


News from Frank in St. Paul, MN

Here I am spraying SPI grey epoxy primer for my interior finish. This stuff is amazing, it sticks like crazy to bare aluminum and is very tough and scratch resistant. Plus, it has a mild sheen to it that doesn’t show scuff marks.

I had hoped to get everything painted before it got too cold to paint, but I didn’t make it. My paint requires a minimum of 65 degrees overnight for the paint to cure properly – I won’t see that kind of temperature in my unheated garage until next June. The plane is ready for painting, but that’s not going to happen until next spring. I’ll continue to do what I can on the plane in the garage until it gets too cold to work out there.

Here is the lower cowl primed. I made a recessed mount for my landing light. I also straightened out the lower lip of  the radiator opening and got rid of the sagging corners.

Engine cowl primed with SPI epoxy primer and mounted. I spent a lot of time working on the cowl. It took a bit of work to get the two cowl parts to fit well together and have a smooth uniform gap without any bulges. I didn’t like how the two carb clearance bumps on the cowl top were shaped, so I made them into more of a proper teardrop shape. I spent the most time on the louvers getting them formed into a uniform shape and size and sitting on a level surface. Some of the louvers were paper thin and I made them thicker in order to prevent future crushing issues.

Congratulations on the Merlin Lite video by Dan Johnson. I think you are going to sell a lot of these.




If you ever have any potential Merlin customers in my part of the country I would be happy to make my plane available for inspection.




Merlin Lite Introduced at the Midwest Expo!

The Merlin Lite has gone public! The first post was by Dan Johnson and has gone viral with nearly 20,000 views in the first 2 days! A record for Dan’s popular site:


Here are some questions and answers from a journalist in South Africa:

  1. What made you design and produce this little craft? Modern technology. The majority of Part 103 ultralights are still tube and fabric and cables. It has been very challenging and capital-intensive to design and manufacture a more conventional aircraft that can meet the strict Part 103 parameters of weight and stall speed. But now with 3D CAD systems and match-hole technology punch presses it is possible. And we proved it at the Midwest Expo by bringing scales with us and proved we were 8 lbs. under the limit! Customers can include paint and more complex instrumentation now and still be compliant. But of course more important is that they have the pleasure and comfort and security of flying an aircraft that has the looks and feel of an aircraft.
  2. I am interested in the  ‘magic’ feature of an electric trim and why you felt it necessary to include this> We include a LOT of features rarely, if ever, found in ultralights like the EFIS, phone charger, electric trim, flaps, windows, air vents, cabin heat, defroster, etc. Most of these items don’t add much to the cost or weight but add a lot to the impression and value of the aircraft.
  3. Who are you aiming at buying your craft? We do not have such a defined market as this style aircraft is both new and has a wide appeal. Low cost flying without burdensome regulation.

The Merlin Lite certainly attracted a lot of attention at this show. Today is the last day then back to Dayton to continue preparation for test flights then production.


Above photos highlight some of the details and features. Notes:

  • Huge baggage area
  • 5 position 50 degree flaps
  • Racing quality 3-point seatbelt
  • Real throttle
  • Dual independent hydraulic disk brakes
  • Full EFIS and Ipad panel with 2 GPSs, moving map, radar overlay, EMS, charging port, and fuel gauge.

Here is an excerpt from the price list showing all that is included:


We are planning for the first deliveries in January and the order book is open to reserve production slots.

Now back to work.


VTwin Guest Blog!!!!

From my esteemed colleague Ben Bosma, our Vtwin partner:

For my pilot friends;

It’s been awhile since I’ve added an update to my Hybird® project. Not to make excuses, but I’ve been busy with other things. I have a standing rule that no airplane gets built unless you do something every day even if it’s cleaning the shop. I held to that rule whenever I was home.

Here are some pictures of the engine on its mount. The original engine that was in this ship was left-handed which is common for engines with a gearbox upfront which reverses the direction of rotation. The Hybird® is right-handed which is what most US engines, helicopters and jet engines are. If you wrap you right hand around the output shaft your fingers pointing in the direction of rotation your thumb should point away from the engine in the direction of thrust. That’s a right-handed engine. It’s like a right-handed bolt or screw.

So, I have to make a new cowling for this ship. In order to do that I need to make sure the engine is in the right spot and pointed in the right direction.

The engine is not pointed straight down the centerline either left and right or up and down. Based on science (LOL) the engine is pointed to the right and down. There’s a specific amount based on a complex set of equations involving torque, blade angles, RPM, time of day, phase of the moon and lunch that determines the perfect angle.

Since those are all variables we use another technique called TLAR or more commonly “Kentucky Windage” which works like a champ. For you perfectionists the engine is pointed 3deg right and 1deg down. This compensates for most flight conditions and should eliminate a lot of rudder, aileron or elevator trim. All those surfaces have fixed tabs I’ll adjust during flight testing. That involves more yarn, tape and bare-naked eyeballs to achieve perfection.

So, I move the engine to where I want it, fabricate a mount and live with it.

Don’t be deceived by the apparent small size of the tubes on the mount. That’s 4130 chrome molly tubing used in race cars and most aircraft. Super strong, weldable and light.

UPDATE FROM CHIP: The engine mount is finished and now at the powder coaters. Next week we will display this new Vtwin at the Midwest Expo in Illinois along with the new Merlin Lite. This show by default has now become the biggest airshow in USA for 2020. Come visit us!

Pop quiz: TLAR is short for? Us engineers use it all the time. Answer in the next blog.


Revolutionary New Part 103 Ultralight

Revolutionary? That’s a bold claim. But I think I can back it up. Here is an excerpt from our forthcoming press release:

Dayton, Ohio: Aeromarine is making the bold claim that their new Part 103 ultralight aircraft is truly revolutionary. “This is not your 1980s ultralight’ claims designer Chip W. Erwin. “I know, I was there. Our new Merlin Lite has real aircraft features and appeal: 7 windows, a door, a cockpit, baggage capacity and space, an instrument panel. And the list goes on”.

The Merlin Lite is based on the Merlin, a popular single seat personal sport aircraft that costs under $40k and cruises at 120mph. The cockpit size of the Merlin Lite is nearly the same size and capacity as the Merlin but the powerplant is scaled down and the wing aspect ratio is increased.

The extensive features INCLUDED or available with the Merlin Lite are not often found on your typical tube & fabric ultralight:


The Merlin Lite meets the FAA Part 103 rules which means no license, medical, registration or certification required. The first public display will be at the Midwest Expo in Mt. Vernon, Illinois beginning September 10, 2020.

Here are some photos form the shop. The BRS is now installed. This week will be the big push to finish the Merlin Lite so we can bring it to our booth at the Midwest Expo. There is still a lot of work to do but I think we are on target. Tundra tire axles are being welded up this week. Fuel tank is nearly finished. Panel is finished. Controls are mostly finished. When I am in Dayton I am working long hours on this aircraft and with a customer Merlin build program as well so writing blogs get delayed. But I will make an effort to post more progress photos.


There will be many doubters about our ability to meet the tight Part 103 parameters.  Fine, bring it on! I will bring some scales to the Midwest Expo. Anyone can check their weight on the scales to verify accuracy then we will weigh the Merlin Lite. Currently we are 4.2 lbs under the limit! Others will question our ability to meet the 24 knot stall speed restriction with only a 22 foot wing span. Well, they are right. But what they don’t know is our first Merlin Lite has the speed wing. To meet Part 103 we will install our UL wing pictured above. This wing has a larger wing area and a very long-span 3-hinge Fowler flap. Part 103 rules allow lift enhancing devices. Furthermore, the stall speed is measured with only a 170 lb pilot and maybe a quart of fuel. So bring it on! Revolutionary new ultralight? I think so.

See the Merlin Lite page. I have posted updated pricing and features/options list.


Electric News (Again)

Photo from prototype system 2014 and from July, 2020

I was right 6 years ago when I said electric power would be great in an ultralight. I was wrong to think I could do it myself. Well, I did do it myself, just not good enough to be a commercial product.

Rather than repeat a lot of what I wrote years ago here I will repeat it on my web site instead. Just updated of course. Not too surprising I didn’t have to change much. I knew then that viable electric power was dependent on battery energy density which was only improving 5-7% per year. That also proved true.

Now I am finally using a system from a supplier I have known for years and with excellent results. You can see our teaser video here: https://youtu.be/CXYo2CfdPb4

We are now offering this ‘plug & fly’ system to our Zigolo customer base and, if we have enough orders, to a new group of Zigolo builders/flyers. I will have a new Zigolo page up today. And here is my retro electric page:   https://www.aeromarine-lsa.com/electric/#top

It costs more than my unrealistic target but IMHO absolutely worth it. Finally, fly low, slow, quiet, and safe.




Congrats to Randi: Airworthiness Certificate Issued!

Last Friday the FAA inspected Randi’s Merlin and with zero snags issued the airworthiness certificate. Randi attended our Dayton, Ohio based build center. Engine test was the day prior to the inspection. This is one beautiful Merlin.

Perhaps Randi will write us a guest blog as he flys the hours off.

Now I have slightly more room in the hangar and will focus on getting the Electrolite flying. Already we have the installation finished:

I will have video and preliminary flight data in a day or so. Only took 5 years…..


So Much News!

I finally made it back to our Dayton workshop where we are backlogged 5 builds. At lease some of them are pretty far along. One customer will have his Merlin taildragger inspected this Friday.

In summary:

*One electric-powered Zigolo “Electrolite” is nearly finished. I expect to fly it this trip.

*One Merlin taildragger with a HKS will get its’ wings tomorrow.

*One Merlin Lite prototype getting controls installed.

*One Merlin with HKS is nearly finished by builder Don.

*One Merlin with 582 is progressing as engine just arrived.

Over-stuffed hangar

Let’s start with the Electrolite. A lot of people have been waiting a long time for some news. Finally I have a professional power system. Installation will be only a couple days. Just as soon as I have room I will put the wings on and fly. Expecting 30 minutes. This will be fun.

On to the Merlin Lite. We will have a few versions of this aircraft. Long wing for Part 103 and to double as a motor-glider. Short wing for faster ultralight for those that register as an E-AB. Polini 250DS engine. And likely electric power after we test our system on the Electrolite.

With all that is going on in the world today it is refreshing to get back to work and to offer affordable aircraft that are truly fun and exciting to fly and actually have some viability as personal transport at 120 mph, or as clean, quiet electric flight.

This will be a big year for Aeromarine as we finally complete some new designs. Next blog will have more news on the VTwin, if flying the Electrolite don’t dominate our headlines.

CWE, Dayton, Ohio.

Road Trip – Finally. And a Merlin Lite update

I have been locked down in our Florida pool home on a private ski lake for over a month. I am only skiing once a day. Sigh. And the last container of aircraft and floats has been quarantined in our Dayton hangar. But from May 1st with the restrictions lifting I can finally make a long road trip starting with the transport of a set of floats and some 737 jacks to Dayton.

Loaded and leaving sunny warm Florida.

Our Dayton hangar has been totally packed with 3 Merlins, 1 Zigolo, a Merlin Lite, and a set of 1450 floats. The Merlin Lite has been moved out for engine installation and now I am delivering the 1450 floats and a Merlin QBK.

Builder Don helped a lot with the packing. Motive: Make more room for his Merlin build.

First stop from Dayton was Green Bay to hand over the 1450 floats. Then on to St. Paul, MN to meet our newest builder Frank. And while in St. Paul I stopped by BRS to pick up the new Merlin Lite 500 parachute.

Frank in St. Paul with his new Merlin QBK.

Now buried in this post a small Merlin Lite update: 1) We ran the engine! That Polini 250DS is super! And the clutch makes it very smooth. 2) New longer wings are in design. This will allow us to meet the 26 nm stall speed. 3) Next step is to install the control system and BRS. We have started this work now and hope to complete it this month. We can begin our test flight program with the short wings and not worry about the stall speed. We know we can meet that parameter. The big task is to verify our empty weight when the aircraft is completely finished. As it stands now we have weighed the components seperatly and are good. Have a look at the first engine test run: https://www.youtube.com/watch?v=hmrd4nU9_qw

Excerpt from the Merlin Lite wing strength calculations
Polini 250DS: Note tempoary fuel tank
Right side. Electric start of course

This will not be your 1980s ultralight: Liquid-cooled, dual ignition, electric start Polini engine. Instrument panel with full EFIS and iPad with Foreflight moving map. Electric trim. All aluminum cantilevered wing airframe. Fully-enclosed cockpit. 3-blade carbon ground-adjustable propeller. BRS rescue system. It even has brakes! Nothing else like it in Part 103 class. Not even close. We are pushing hard to complete and fly it.

Inexpensive yet very sophisticated glass panel. In an ultralight! Air speed, altimeter, G meter, VSI, artificial horizon all on EFIS and more. iPad has Foreflight installed. Wing tip strobes and nav lights. Even a USB power source! My other ultralight has a rain gauge for an ASI. What a contrast.

Welcome to our new website!

Aeromarine has been busy creating new aircraft and power systems. We are getting close to first flights and going public. Our engineers continue their preparation and as soon as I can travel again, we will be back flying. For my 12 blog readers you will have the first look on our new web site.

All our big news was going to be made public at Sun n Fun this month. But now that is cancelled. I sure hope there is an Oshkosh show. We will be much farther along with flying aircraft by Oshkosh and a big booth space to show all. We have so much new and nearly ready to make public that we decided to make a completely new web site.

As those following the Merlin may already know HKS stopped all engine production so the 700E is no longer available. That leaves the Rotax 582 which works great on the Merlin but has a lot less market appeal as it is a 2-stroke engine.

The Aeromarine V-Twin is a 60 hp liquid-cooled 4-cycle 800cc 80-degree fuel-injected, electronic ignition engine with electric start.

CAD design now finished for Merlin installation

The V-twin is ‘red-neck proven’ meaning hundreds of thousands of this engine have been manufactured and put to the test in ATVs. These 4-wheel off-road vehicles are run hard in extreme off-road conditions.  They have proven themselves to be very durable and reliable. Perfect for aircraft use.  Plus, this engine is very modern especially compared to nearly every aircraft engine. It has electronic ignition and fuel injection. And designed to be run at high power settings.

With the new engine we needed a carbon ground-adjustable prop perfectly matched to it. That work was commissioned and finished. Our first props just arrived.

NEW Aeromarine carbon propellers!

Another big piece of news not quite ready for public disclosure is our new Merlin Lite aircraft. Lighter than the Merlin? Hard to do but possible as we are targeting the tight Part 103 Ultralight rules. Our math shows that we can do it. This means you can have a smaller, lighter Merlin for even less money and even less regulation. You need more paperwork to fly a drone or remote-controlled aircraft than for the Merlin Lite!

Power will be a small Polini PPG engine to start and possibly electric power if I ever manage to get that finished.

We just received a container of Merlins, a set of floats, and our first Merlin Lite and despite all the world drama and Florida & Ohio lockdowns we managed to unload the container.  Frustrating to have all these kits to deliver to customers and the new Merlin Lite to finish and I am stuck in Florida. At least our ski lake/seaplane base is still open.

Here is the brochure prepared for SNF now well in advance and likely outdated by the time the show rolls around:


Personal Sport Aircraft