Aircraft Tools Blog

Build Your Own Aircraft Engine Preheater!

I have spent considerable time studying airplane engine preheaters.  Those engine preheaters that I conducted reviews on included the Aerotherm, Hornet, EZ or E-Z, Tannis, Safe Heet, Reiff, and the Red Dragon.  After my aircraft engine preheater reviews I concluded that some types are better than others to protect your airplane during cold weather.  My airplane engine preheater reviews also concluded most of these units are very expensive, suggesting you are paying for the word “aircraft” or “airplane” preheater.

After these preheater reviews I set out to build my own aircraft engine preheater. It turned out that I could build the best type of engine preheater for my airplane for less than $100 using simple tools and parts.  The aircraft engine preheater took less than three hours to build and it works great!  In addition, my heater can provide heat for the inside of the cockpit which will protect the interior components of your airplane.

My aircraft engine preheater includes a thermostat to control the temperature of the ceramic heating element so it only runs when the outside temperature drops to a point where it is necessary to preheat the engine.  The airplane engine preheater has two power settings including low watts and high watts.  During cool weather I can set it on the lower setting and the unit keeps my aircraft engine warm.  During severe cold I can set my airplane engine preheater on the higher watt setting and it assures my engine is ready to go in the extreme cold weather.  The unit also has a safety overheat protection system.  The system uses standard 120 volt service.

Evenly preheating the aircraft engine in cold weather is important to reduce wear and tear on the pistons, cylinders, camshaft and other internal components which will help extend the hour life.  Oil heaters do not provide even heating of the engine and can induce condensation internally which causes corrosion and rust.  My design using heated air circulation reduces the possibility of condensation preserving the engine life.  In addition, using an insulated cowl cover will help keep the heat even in the aircraft engine compartment.

I took great care in documenting the materials and build process to make this aircraft engine preheater.  The plans will be available on our website for a very low cost.  If you don’t want to spend $500 plus on a really good engine preheater for your airplane consider building this unit for less than $100.

RV-12 Pop Riveting in Tight Spaces

When the RV-12 originally was developed the build process called for a PRP-26A tight space pop riveter.  This tool was used to pull pop rivets that were too close to other structure to allow room for the tool to pull the rivet.  Emhart, the manufacturer of the PRP-26A riveter, "retooled" for this riveter.  When they did the new tooling cost allocation drove the price of this hand riveter to about $150, an outrageous price. 

Because of this many builders have used many different ideas to come up with a way to pull these rivets.  The best resource for tight space rivet tool is this EAA video:

Tight Space Pop Riveting

Our RV-12 kit includes a pop riveter that can be modified (ground off) to remove much of the nose piece to allow for meeting most of the tight space requirements.  This has worked well for our builders.  We are continuously looking for alternates to improve the building process for our RV-12 builders.

Let us know ifyou have come up with any better ideas on the RV-12. Keep up the great building!

 

Springback versus Regular Aircraft Dimple Dies

Many of our RV Aircraft builders have ask what the difference is between a Springback and regular dimple die. The concept behind springback dies are that the aluminum is "canned" in the opposite direction of the dimple (1-1/2 degrees) which allows the aluminum to "Spring back" into a flat sheet around the formed dimple. A regular dimple die may leave a slight can around the dimple, in the same direction as the dimple. Springback dimple dies were developed by the Aluminum Company of America in 1942 under contract for the National Advisory Committee for Aeronautics. Since that time there are a few tool companies put out the false illusion that they invented the springback dimple dies, or that they have significantly improved them. We have measured and tested all of these dimple dies and the bottom line is the springback dimple dies work pretty well on 1/8" or larger diameter countersink holes, and all of them work the same with no noticeable difference in the finished product. The technique of dimpling also affects the finished dimple and "canned" effect. On small Number 40 rivets we find that a standard die works as well as the springback dimple dies. Many will argue these points, but they will also say that they invented this 1942 tool. The best dimpled hole is one that has the rivet "set" with the actual rivet that will fill the hole.  Use a dimpling block to set the rivet just before driving and bucking it. 

To make a dimpling block, simply drill a hole slightly larger than the rivet diameter in a piece of steel or a bucking bar.  Next, countersink the steel so that the dimpled skin will lay against this countersunk hole.  Then, Install the rivet, hit it 2 or 3 times with the rivet gun lightly to set the rivet into the skin.  Buck the rivet.  This process gives you a perfectly set flush rivet every time.  This is the way the many commercial manufacturers install flush rivets to make commercial airplanes flawless.

Deburring Rivet Holes

We receive many questions regarding deburring of rivet holes. After drilling and installing hundreds of thousands of rivets I can say with some professionalism that you do not need to deburr rivet holes in thin aluminum skin or ribs using a deburring tool that cuts away the metal. What is generally left in the hole is not a burr, but is a hangnail or chips left over from the drilling operation. You can easily remove chips by de-clecoing the parts, use a heavy pair of cotton gloves and lightly run your hand across the drilled sheets. What must be avoided is removing the aluminum from around the edge of the hole.  The holes should be crisp and clean, not countersunk from removing material. If you do have an occasional burr (a piece that you cannot remove by rubbing) you can remove it by using a countersink bit and lightly turning it by hand to remove the burr.  In non-pressurized aircraft perfectly round holes are not necessary.  If you were building a pressurized airplane you should ream every hole and make sure they are perfect to preclude any cracking of skin around the rivet.  This is also true in non-pressurized critical structures, as example, a wing spar that may see high loads.  But on most parts this is overkill since the structure will not see any pressurization cycles during its service life.  Save some time and headache and do not over deburr. 

210 Horsepower STC for Cessna R172K 'Hawk XP

Over 400 Cessna R172K owners have installed our 210 horsepower conversion on the 'Hawk XP airplane.  The conversion is relatively simple to accomplish.  The original 195 horsepower at 2,600 RPM is reconfigured to 210 horsepower at 2,800 RPM.  The modification requires overhaul of the propeller governor, overhaul and remarking of the tachometer and manifold pressure/fuel flow gauge, and resetting of the low pitch stop on the propeller.

The additional horsepower all goes to acceleration on takeoff and increased rate of climb making the Cessna R172K an extremely high-performance airplane.  You may find more information on our web page under the Isham Cessna 210 horsepower modification or on our catalog page.

Setting Up a Pneumatic Squeezer

Set up of the squeezer is slightly different depending on the type of work being done.

When riveting with the squeezer start with a gap (while the squeezer is fully activated) that is equal to the skin thickness plus the length of the "finished" rivet.  After the rivet is set, the butt of the rivet should be within tolerance.  If it is squeezed too much, add shims or fine adjust the set holder so the butt of the rivet is the correct length.  If it is too long, shorten the gap by removing shims or adjusting the adjustable set holder.  A rivet is better when squeezed too little than to much.

When dimpling, the dimple dies should touch each other slightly without any gap.  The male die should be installed in the fixed part of the yoke and the female die should be in the fixed set holder that moves up and down when activated.  When dimpling, place the aluminum part over the male set holder and trip the squeezer trigger very fast and at full throttle in order to "slap" the dies together and create a nice crisp dimple.

Do not have less than "zero" gap when dimpling as pneumatic squeezers have enough power to spring the yoke.  Never use an adjustable set holder for dimpling as it will damage the threads on the set holder.  Most yokes have a slight spring during dimpling and riveting but go back into the original position.  If dimpling with negative clearance you could permanently deform the squeezer yoke.

RV Aircraft Tool Kit Shipping

Over the years Isham Inc. has exported hundreds and hundreds of Van's RV Airplane Tool Kits to our RV tool kit customers.  Generally our shipping cost for shipping an export RV tool kit is 1/3 to 1/4 of the cost compared to standard shipping methods like UPS or FedEx.

In some cases special approvals are required by the importing country. These approvals include US Chamber of Commerce and foreign Embassy approvals for some countries. Whatever the requirements are we will work hard for our customers to obtain the proper approvals to make the importing of our RV tool kit to your country as seamless as possible.

If your Van's RV Airplane kit is being shipped by ocean freight it may be possible to combine your aircraft tools with the shipment of your airplane kit.  You will need to do a little coordination to determine the projected shipping date of your airplane kit and we can coordinate your airplane tools with the shipping exporter.  This can save a great deal of money and your airplane tools will arrive at the same time as your airplane kit.

Full details of the RV tool kit can be found at www.PlaneTools.com as well as your ability to obtain a shipping quote for an export kit.

HOW TO MAINTAIN AIRCRAFT SHEET METAL TOOLS

Proper maintenance of your aircraft tools is necessary.  If tools are used daily you generally will not have any issues.  All tools need a light coat of oil to preserve them during storage.  There are many environmental elements that can make tools rust.

1.      Tools are designed to be used daily.  Without daily use you need to take some special care to prepare them for storage.  Most builders of Vans RV aircraft need to take preventative action to protect their airplane tools from rust.

2.      Clean and wipe down tools with a light coat of oil before putting them away.  Keep an oily rag handy for that purpose.  A light coat of oil will remove the moisture from your hands and protect the tools during storage.  WD-40 is a good preservative for tools.

3.      If possible, store tools in a controlled environment.  Without temperature control your tools will sweat and rust.  If you heat your storage area with a propane or kerosene heater you will cause your tools to rust.  Both of these heaters produce water vapor and the cold tools will collect this moisture until the tools reach room temperature.  The main prevention of rust on tools is to control humidity.

If your tools do have surface rust clean them as soon as possible.  There are several methods of which any will work.

1.      Use a Scotchbrite pad to remove surface rust and wipe the tools with a light oily rag.  WD-40 would be a good oil to use.

2.      Very fine steel wool will remove the rust. 

3.      For round tools (rivet sets, die sets, etc.) you may want to place them in a drill and polish them with a polishing wheel on a grinder.  Use a light buffing compound to make them new again. 

4.      For flat surface tools (bucking bars, flush rivet sets, back rivet plates, etc.) use fine steel wool to clean the rust.

5.      In all cases, wipe and coat with oil.  Check them occasionally if not used. 

All aircraft tools need to be protected against rust.  Here are some:

1.      Rivet bucking bars, rivet squeezer yokes, rivet gun springs, rivet gun sets, back rivet sets, countersink bits, rivet squeezer sets and dimple dies need to be wiped with an oily rag.

2.      Clecos need to be continuously dry.  Keep them in a protective bucket with an air tight lid.  Each time you store them spray a little WD-40 in the bucket before closing the lid.

3.      Hand tools such as tin snips and deburring tools should be wiped with an oily rag.

4.      Unless the tool manual states otherwise, pneumatic tools need to be oiled with a few drops of oil at the end of the work shift.  Also, wipe the outside surface of unpainted tools with an oily rag before storage.

A small amount of maintenance will keep your tools in great condition so the next time you use them they will be free from rust.