{"id":9250,"date":"2022-06-23T14:13:18","date_gmt":"2022-06-23T18:13:18","guid":{"rendered":"https:\/\/volareproducts.com\/blog\/?p=9250"},"modified":"2022-06-23T14:13:18","modified_gmt":"2022-06-23T18:13:18","slug":"dts-dethermalizers-mysterious-complicated-are-you-ready","status":"publish","type":"post","link":"https:\/\/volareproducts.com\/new2024\/dts-dethermalizers-mysterious-complicated-are-you-ready\/","title":{"rendered":"DTs – Dethermalizers – Mysterious? – Complicated! – are you READY?"},"content":{"rendered":"

Dethermalizers<\/strong> – the Next Big Step in your Free Flight Evolution.\u00a0 Beginners often ask a lot of questions, especially on the field while watching.\u00a0 One that I often answer in the negative is “do I need a DT?” – or – “what stuff do I need for a DT?”\u00a0 What I tell beginners is “until you start building, trimming, and flying well enough that your models are repeatedly flying away, you do NOT need to complicate your modeling with DTs.\u00a0 Come back when you are having models fly away and I’ll help you out.”<\/p>\n

Why do I say this?\u00a0 Because the beginner needs to learn to build, trim, and fly.\u00a0 There is no sense in putting a DT on a model that isn’t trimmed to fly for more than 30 seconds.\u00a0 Those three initial skills need to be developed to the point that the model is capable of flying OOS before the modeler needs to worry about how to install and operate a DT.\u00a0 Until that time, it is an unnecessary complication.\u00a0 I flew for a couple of decades before I started installing DTs.\u00a0 And since then, I’ve put on plenty of DTs that don’t get much action (because the plane isn’t up to snuff, yet).<\/p>\n

So, bunkie, you lost your plane?\u00a0 You’ve lost several?\u00a0 Then you need the Salvation of Free Flight – the DETHERMALIZER!\u00a0 (No, not the Korda Dethermalizer<\/a> OT Cabin – Class D 1941 Nats Winner – WITH a DT!)\u00a0 A properly working (hopefully #1)<\/strong> DT will disturb the balance of your perfectly soaring model and it will no longer be able to soar efficiently and it will be kicked out of the thermal and descend to the ground (hopefully #2<\/strong>) and save your model (hopefully #3<\/strong>).<\/p>\n

Hopefully #1<\/strong> – DT’s, regardless of their type (see below), can malfunction.\u00a0 During the construction of your model and installation of the DT, you will want to ensure that the operation of the timer and of the release are smooth and glitch-free.<\/p>\n

Hopefully #2<\/strong> – Sometimes, properly functioning DTs are overcome by the strength of the thermal and they sail off Out-Of-Sight, regardless of how smooth and perfect the operation.\u00a0 A different style of DT action (see below) might have saved the model.\u00a0 Also, “where” the model comes down may prohibit retrieval – maybe it is stuck high in a tree, or in the middle of a lake, of somewhere else where you cannot find it.<\/p>\n

Hopefully #3<\/strong> – sometimes the model will descend to the ground, but because of the type of DT action or some freak occurrence (tangled lines, etc.), the model will suffer damage when it hits the ground – or whatever it hits.<\/p>\n

Dethermalizers have been around since the late ’30s or early ’40s.\u00a0 As mentioned above, Dick Korda named a model he designed “Dethermalizer”, possibly because he integrated a DT into the design.\u00a0 This article won’t be so much of a How-To, but more of a discussion the types of Actuators<\/strong> and the types of Actions<\/strong>.\u00a0 All of the DTs that I know of have an Actuator that control when and how the DT Action takes place.\u00a0 And the model design incorporates a method of Action.<\/p>\n

Types of ACTUATORS<\/strong><\/p>\n

Actuators are the things that count down the time and trigger the Action.\u00a0 Count down the time?\u00a0 Yes – you want the DT to operate after a set time and not before.\u00a0 This time will be determined by YOU, the Builder and Flyer.\u00a0 Most of the time, I set my TIME based on the maximum official flight time (most often – 2 minutes).\u00a0 Sometimes, I will set the time shorter and this decision is based on the field conditions – maybe it is a small field, or a particularly windy day and 2 minutes will carry the model off the field.<\/p>\n

Regardless, all types of Actuators are basically switches that, after an assigned time, the “switch” is activated and the Action is initiated.\u00a0 I will now discuss the various types of mechanisms that we most often see on the flying field (I won’t be discussing the antique Austin timers, although they still work).\u00a0 Here are the types I will be discussing:\u00a0 Burning Fuse<\/strong>, Mechanical\/Clock<\/strong>, Viscous\/Button<\/strong>, Electronic<\/strong>.<\/p>\n

BURNING FUSE<\/strong><\/p>\n

This is one of the simplest and possibly most reliable DTs that we have.\u00a0 It is basically a short piece of cotton cording that has been impregnated with a chemical that burns easily.\u00a0 This fuse is lit with some sort of lighter (my favorite is an electronic, rechargeable, arcing-plasma lighter).\u00a0 The fuse fits snugly into an aluminum tubing with a short length extended.\u00a0 Generally a small rubber band is lightly wrapped around the fuse close to the tubing and as the fuse smoulders and burns down, it will contact the rubber band and melt or burn it and the release of the rubber band triggers the Action.\u00a0 The snug installation into the aluminum tubing will extinguish the burning fuse.<\/p>\n

\"\"<\/a>

a Burning Fuse installed on the tail of an Embryo model. The length of fuse from the exposed end to the small rubber band regulates the amount of time before the Action is triggered.<\/p><\/div>\n

The SWITCH:\u00a0 burning through a rubber band that is preventing the ACTION<\/p>\n

Benefits of the Fuse Type:
\n– cheap
\n– installation is generally simple
\n– it is relatively light weight
\n– it is generally very reliable<\/p>\n

Downsides of the Fuse Type:
\n– they are dependent on an igniter – a lighter of some sort – and electronic ones need to be charged.
\n– setting exact time is a guessing game as the rate of burn can vary with conditions
\n– if the fuse is damp or the day is rainy, the fuse may not light or stay lit
\n– a poor start of the burn can extinguish and result in no DT
\n– FIRE – these use live fire and they can start fires
\n– some modelers have burnt their models while lighting the fuse
\n– if the model lands before the desired time, the fuse\/fire could light the grass on fire
\n– as a fire hazard, this type is PROHIBITED in some locations<\/p>\n

Overall, these work well.\u00a0 If the fuse is lit properly, it WILL burn down at a regular rate and it will self-extinguish.\u00a0 Just make sure your rubber band is tight against the fuse and your Action is positive and you will have a light-weight, reliable Actuator.<\/p>\n

MECHANICAL\/CLOCK<\/strong><\/p>\n

These are called “Clock” types because of the way they work:\u00a0 you wind a spring and it unwinds; just like an old-fashioned clock or watch.\u00a0 There are commercial versions or you can make your own.\u00a0 Being “clocks”, they have a very reliable countdown.\u00a0 The spring is regulated somehow to slow the unwinding of the spring.\u00a0 There are some very complicated multi-function Clock Timers.\u00a0 These are used to manage several aspects of the model’s performance:\u00a0 engine shut-off, variable incidence tails, DT action.\u00a0 The ones shown here are simple, single-function timers.<\/p>\n

\"\"<\/a>

Mechanical\/Clock DTs. In the back are examples of a Commercially-produced single-function Mechanical DT. In the front is a home-made one. The arms with weights are added to regulate the rate at which the spring unwinds.<\/p><\/div>\n

The SWITCH: usually the unwinding and release of a line that is preventing the ACTION<\/p>\n

Benefits of the Mechanical\/Clock Type
\n– these are very reliable – they count down at a constant rate.<\/p>\n

Downsides of the Mechanical\/Clock Type
\n– they are often too heavy for small models
\n– commercial versions are becoming very hard to find
\n– homemade versions take a little bit of experimentation to get them to work right
\n– homemade version require a wind-up toy – not all wind-up toys have the right clock
\n– they can get dirt in them
\n– I have had them “not work” but that is probably lack of skill in construction or setting<\/p>\n

VISCOUS\/BUTTON<\/strong><\/p>\n

Sometimes these re referred to as “Button” timers – Bob Munson perfected the viscous timer and had a Button (small) and a Badge (larger) version.\u00a0 Homemade versions usually are made from rotary dampers that are found in various automotive applications:\u00a0 slow opening compartment doors, etc are regulated by viscous rotary dampers.\u00a0 All of these work in the same manner:\u00a0 they have a chamber with an oil or compound.\u00a0 In that compound is a “paddle” that is commented to a rotating shaft.\u00a0 The fluid or goo resists the rotation of the shaft and this is usually at a fairly constant rate.<\/p>\n

\"\"<\/a>

Munson Button and Badge Viscous Timers.<\/p><\/div>\n

\"\"<\/a>

a homemade Viscous DT Kit that used a commercial rotary damper<\/p><\/div>\n

 <\/p>\n

There is another homemade viscous type that is made with aluminum tubing and Silly Putty.\u00a0 These can be made with a little work.\u00a0 You can find instructions HERE<\/a> (PDF in the FAC Library).\u00a0 There is an early version where a “trench” in the glider fuselage was filled with Silly Putty and a wire dragged through it.\u00a0 I cannot find a link to that right now.\u00a0 There are several how-to’s online regarding the tube\/Putty versions.<\/p>\n

The SWITCH: usually the unwinding and release of a line that is preventing the ACTION<\/p>\n

Benefits to the Viscous\/Button Type
\n– they are lightweight
\n– the original Munson timers were very reliable (current version, not so much)
\n– homemade versions are cheap to make and material is available<\/p>\n

Downsides to the Viscous\/Button Type
\n– some are temperature-sensitive
\n– all are dependent on a constant rate-of-pull (rubber band, spring, etc.)
\n– pull sources do not always have a constant rate of pull.<\/p>\n

ELECTRONIC TYPE<\/strong><\/p>\n

Some electronic gurus have been able to produce electronic countdown timers that are light weight and programmable.\u00a0 The results are a relatively light appliance that is very reliable and very<\/strong> accurate – to 10 seconds; some are to the single second.\u00a0 There are now various products, some with multi-function, some are band burners, some trigger micro servos, and some with battery chargers built in.<\/p>\n

\"\"<\/a>

one type of commercially available Electronic DT<\/p><\/div>\n

The SWITCH: burning a rubber band or activating a servo that is preventing the ACTION<\/p>\n

Benefits to the Electronic Type
\n– very reliable and very accurate
\n– relatively light weight
\n– installed properly, they can be swappable between models.<\/p>\n

Downsides to the Viscous\/Button Type
\n– some are very expensive
\n– all require programming that can be complicated
\n– all require on-board micro-batteries that need charging
\n– the batteries are so small (capacity) special chargers should be used
\n– charging on the field requires a power supply
\n– band burners may break the thin ni-chrome wire
\n– band burners require light rubber bands that WILL burn with the short hot pulse<\/p>\n

All of the types listed above do one thing:\u00a0 they provide a predictable delay from the start to the time the “switch” initiates the ACTION.<\/p>\n

Types of ACTIONS<\/strong><\/p>\n

The ACTION is what takes place once the “switch” is thrown.\u00a0 These Actions can take place on the Tail, or on the Wing, or Other locations.<\/p>\n

TAIL<\/strong><\/p>\n

Probably the most common is the Tail DT where the horizontal stab is hinged.\u00a0 Typically a fine line is run from the tail, along the side of the fuselage, to be connected to the DT.\u00a0 When the DT activates, the line is released and the tail, hinged at the front (usually), pops up (due to spring loading or a rubber band pulling) to about 45 degrees – like up elevator to an extreme.\u00a0 This will cause a nose-up condition in flight that balances out and the model sinks slowly and flatly to the ground.<\/p>\n

The Tail-type is probably the easiest to install and operate, although there has to be enough tension in the line to keep the tail in flying position and not allow it to creep into even a degree of “up” where none was intended.\u00a0 Also, Tail-types “can” still be carried away by a strong thermal, even after the DT Action takes place.\u00a0 It is not common, but can happen.<\/p>\n

Some models, because of the design where the tail intersects the fuselage, will require a two-piece split horizontal tail pivoting on a rod\/tube combination.\u00a0 These are more complicated installations, but Scale models often require this if the Tail Type is chosen.<\/p>\n

\"\"<\/a>

the previously-shown Fuse-type DT and the Horizontal Stab popped up.<\/p><\/div>\n

\"\"<\/a>

a Scale model with at Split Horizontal in DT’d position.<\/p><\/div>\n

WING<\/strong><\/p>\n

Some models – and modelers – prefer a Wing DT.\u00a0 There are two types here, too:\u00a0 a Pop-Off Wing and a Pivoting Wing.<\/p>\n

A Pop-Off Wing DT does just what it says:\u00a0 once the Action takes place, the wing becomes detached from the model and all aerodynamic function is lost.\u00a0 The plane falls to the ground – sometimes very rapidly (possibly damaging the model).\u00a0 The wing is typically attached to the fuselage by a long string and, if done right, can act like a maple leaf and slow the descent.<\/p>\n

Another type is the Pivoting Wing DT.\u00a0 Similar to the Tail DT, the wing is hinged at the Trailing Edge.\u00a0 Again, the desired angle is about 45 degrees.\u00a0 This causes the same disruption as the Tail DT, but instead of a flat descent, the descent is nose-down and generally faster.\u00a0 Again, this can result in damage to the model.<\/p>\n

The legendary Jack McGillvray had a Fairey Barracuda that pivoted the wings at the high point.\u00a0 You can watch the video HERE<\/a> thanks to Tom Hallman.<\/p>\n

\"\"<\/a>

hard to see, but there is a Burning Fuse DT in the middle of the wing. The Fuse burns the rubber band and the wing pops off. The tip of the wing is attached to the tail of the fuselage by a fishing line.<\/p><\/div>\n

\"\"<\/a>

hard to see, but this is a Wing DT that pivots at the Trailing Edge.<\/p><\/div>\n

OTHER<\/strong><\/p>\n

There are other less-common Actions.\u00a0 In Hand Launch Gliders, some would use a section of pop can on the fuselage.\u00a0 It laid flat while under normal flight, but the Action would release it and the natural curl of the aluminum can would disrupt the airflow around the fuselage and spin the glider down.<\/p>\n

Other gliders use a more modern DT where the fuselage pivots just behind the wing. This is a very positive Action.<\/p>\n

Returning to the ’40s, Chet Lanzo created a model<\/a> where the wing went through the cabin and the upper part of the cabin was hinged at the rear and popped up, causing a disruption in the glide.<\/p>\n

SUMMARY<\/strong><\/p>\n

This is not meant to be THE definitive paper on DTs.\u00a0 I am just sharing common types of Actuators and Actions for the person just starting into DTs.\u00a0 It will give them things to consider.\u00a0 I am sure that my lists of Actuators, Actions, Benefits, and Downsides are incomplete – you may have pages to add, but this is what I came up with this afternoon.\u00a0 And lastly, how you route the lines and adjust for travel and such is clearly not included in this writing.<\/p>\n

Of course, one should always research the subject.\u00a0 There are tons of articles on DTs in the FAC Library<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Dethermalizers – the Next Big Step in your Free Flight Evolution.\u00a0 Beginners often ask a lot of questions, especially on the field while watching.\u00a0 One that I often answer in the negative is “do I need a DT?” – or … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":9254,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-9250","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-builds"],"_links":{"self":[{"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/posts\/9250","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/comments?post=9250"}],"version-history":[{"count":0,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/posts\/9250\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/media\/9254"}],"wp:attachment":[{"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/media?parent=9250"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/categories?post=9250"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/tags?post=9250"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}